Evaluation of Native Plant Seeds 

and Seeding in the East-Side 

Central Cascades Ponderosa Pine 

Zone 

Nan C. Vance 

United States 

Department of 

Agriculture

Forest Service

Pacific Northwest 

Research Station

General Technical 

Report

PNW-GTR-823

November 2010
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multiple use management of the Nation’s forest resources for sustained yields of wood, 

water, forage, wildlife, and recreation. Through forestry research, cooperation with the 

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growing Nation.

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Author

Nan C. Vance is a research plant physiologist (emeritus), Forestry Sciences

Laboratory, 3200 SW Jefferson Way, Corvallis, OR 97331.

All photographs by Nan Vance.
Abstract 

Vance, Nan C. 2010. Evaluation of native plant seeds and seeding in the east-side 

central Cascades ponderosa pine zone. Gen. Tech. Rep. PNW-GTR-823.

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 85 p.

In dry, open coniferous forests of the montane West, stand-replacing wildfires and 

land use activities alter the composition and abundance of native grasses and forbs 

by degrading the habitat and accelerating the invasion of exotic annuals. On these 

lands, native forbs and grasses delayed or prevented from recovery by natural processes may require intervention through supplementary seeding. However, effective 

seeding of native plants requires that their seed traits and the potential outcome of 

the seeding be better understood. This study evaluated seeds and seedlings of 13 

native forbs and 5 grasses common in the dry Pinus ponderosa/Purshia tridentata/

Festuca idahoensis plant communities east of the Oregon Cascades crest and their 

potential for establishment in a landscape altered by past grazing and a recent, 

stand-replacing wildfire. Their potential for germination and establishment was 

examined in the laboratory and in 20 test plots located within the burned boundary 

of a 2002 wildfire. Seed collection, handling, testing, and sowing procedures are 

described. Data on seedling emergence, height, second-year survival and cover are 

presented in tables and figures. Onsite emergence and early growth data helped to

reveal cause of early mortality related to biological and site conditions, including 

invasive competition, and differences in early growth and site occupancy. The 

study supports the efficacy of using multiple and functionally diverse species in a 

seeding program. Additional information on each of the 18 species is included in an 

appendix.

Keywords: Postfire rehabilitation, native forb, native grass, Pinus ponderosa/

Purshia tridentata/Festuca idahoensis plant association, seeds, seedlings, east-side 

central Oregon Cascades.
Preface 

A series of executive orders and regulations by the USDA Forest Service recognize 

that sustainable ecosystems require the maintenance of native plant and animal 

diversity. The Forest Service Manual (FSM 2070) provides direction for the use, 

growth, development, and storage of native plant materials for revegetation, restoration, and rehabilitation of National Forest System lands to support its goal of 

protecting and conserving biological diversity. Inherent in this directive is the use 

of best available information for developing native plant materials most adapted 

to a site or situation; particularly in cases where natural regeneration sufficient to 

restore the native plant community is unlikely. 

Contents

1 Introduction

1 Background

2 Study Objectives

3 Species Assessment

3 The Site

7 Seed Evaluations

16 Species’ Performance on Site

26 Summary and Conclusions

28 Glossary

31 Acknowledgments

31 English Equivalents

32 Literature Cited

44 Appendix 1: Growout Results at Lucky Peak Nursery

47 Appendix 2: Summarized Information by Species
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Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Introduction

Background

The dry montane forest zone where Pinus ponderosa is dominant or codominant is 

one of climatic extremes with shorter growing seasons and less annual precipitation 

than other forest zones (Franklin and Dyrness 1973, Simpson 2007). In Oregon, 

the P. ponderosa series forms a band along the east-side Oregon Cascade Range. In 

this band, even during the moist growing season from March through June, there 

are extreme fluctuations in temperature. Fire intervals in the P. ponderosa series 

were historically short and wildfires relatively light resulting in herbaceous vegetation dominating the understory. However, in recent years, wildfires occurring at 

longer intervals have tended to be larger and of higher severity (Agee 1994). In this 

semiarid ecosystem, recovery of the long-lived perennial grasses and forbs is slow 

even in plant communities highly adapted to periodic fire (Johnson 1998). However, 

sheep grazing, timber harvesting, and mechanized fire-control activities since the 

early 20th century (USDA FS 2004b), plus stand-replacing wildfires and spread 

of exotic annuals hinder the recovery or even irreversibly alter the native plant 

communities (Evans and Young 1978, Merriam et al. 2006, Monsen et al. 2004, 

Whisenant 1999). 

Reduced grass cover and lack of shrub cover followed by severe wildfire 

removes almost any impediment to colonization by nonnative annual grasses, 

which, if they are present, will rapidly invade the postfire landscape (Arno 2000, 

Johnson 1998, Young and Evans 1978). In addition, seeding of annual and perennial 

nonnative grasses for postfire soil stabilization assumes that the germinated nonnative grasses would not persist after 2 years or be competitive with native species, and possibly, would function as a “nurse crop” for recolonizing native plants 

(USDA FS 2002). However, there is evidence to the contrary (Robichaud et al. 

2000, Schoennagel and Waller 1999). Nonnative cereal grasses used in seeding for 

soil stabilization tend to persist, tend to interfere with the recovery of native plants, 

and do not prevent the almost inevitable expansion of exotic grasses and forbs if 

they are at all present in the area (Beyers 2004, Keeley 2004). 

Wildland rehabilitation that is directed toward increasing the abundance of 

perennial native forbs and grasses should address the importance of diverse life 

forms and niche species. One goal of a rehabilitation plan might be to target keystone species and diverse functional groups. It should be emphasized, however, 

that sowing native forb and grass seeds on lands altered by severe wildfire will 

not re-create a prefire plant community. Fire and other disturbances owing to fire 

suppression activities may change soil, water, and light conditions irreversibly so 

that the trajectory of recovery goes in a different direction. In fact, successional 
2

GENERAL TECHNICAL REPORT PNW-GTR-823

changes that occur after a large fire often will include interim dominance of one or 

two species for years without the subsequent full recovery of native perennial plants 

(Johnson 1998). 

Native forb and grass species appear to perform well in highly disturbed conditions where there is low nutrient availability, and thus could provide long-term 

resistance to annual bromes that tend to invade poorly occupied sites, especially 

following disturbance such as wildfire (Daehler 2003, Young and Evans 1978). 

Reintroducing a diverse mixture of native grasses and forbs may also help prevent 

or reduce the spread of noxious weeds along roads and in safety zones, dozer lines, 

and culvert replacement areas (Sheley and Half 2006, Tilman 1997). However, an 

impediment to restoring postfire plant communities or rehabilitating degraded landscapes is that the reproductive ecology, seed biology, and establishment requirements of many native flowering species and their symbionts are not well known, 

even those that are relatively common in fire-prone ecosystems of the Western 

United States. This lack of knowledge is one reason there is an increasing reliance 

on developing a small set of “performers” rather than striving for a diverse seed 

mix that would have greater potential to more fully occupy the landscape being 

rehabilitated. Unfortunately, the benefits of forb/grass mixes for seeding in dry 

forest types have not been proven, in part, because of the complexity introduced by 

differences among species in reproductive biology and site interactions that influence establishment rates (Jorgensen and Wilson 2004). Another approach thought 

to ensure enough established plants to inhibit invasive species establishment, is 

to sow at high density a seed mixture that includes aggressive, rapidly colonizing 

species (Sheley and Half 2006). A problem with that approach may be the potential 

for waste of costly seed and the suppression of desired perennials because of the 

colonizing success and later domination of one or a few aggressive, annual species 

(Brown and Amacher 1999, Brown and Rice 2000). 

Study Objectives

This study sought to address the shortage of information on the differences in traits 

and characteristics among forb and grass species that might be used in developing 

a native plant seeding program. Specifically, this study sought to identify traits in 

18 native perennial herbs and their associated environmental factors that affected 

germination success and early establishment in a postwildfire environment in the 

dry Pinus ponderosa plant association on the east-side central Oregon Cascade 

Range. Our approach was to study the seed biology and germination and early 

growth processes of selected species in a controlled seeding across a range of 

micro-conditions in spatially separated plots that would suggest whether they could 
3

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

be effectively used in rehabilitation programs. The approach involved first, collecting, cleaning, storing, and laboratory testing of seeds; second, evaluating germination in the field based on emergence; and third, measuring second-year survival 

and growth of seedlings. The outcome is detailed information on 18 species from 

seed through seedling. The data and discussions on performance in the field and 

laboratory may aid in developing rehabilitation strategies that use native plant seeds 

and help reduce costs by identifying important factors to consider in developing an 

appropriate mix of native forbs and grasses.

Species Assessment

The Site

Description—

The study site and seed collection area are located on 1300 ha (3,200 ac) of National 

Forest System land in Jefferson County, Oregon, under the management of the 

Deschutes National Forest, Sisters Ranger District. The site is on the easternmost 

flank of Green Ridge scarp in the Metolius River drainage and in a dry Pinus

ponderosa series that extends along the eastern flank of the Cascade Range in a 

narrow band (fig. 1). The topography of the study area is primarily a gentle, eastfacing slope (<15 percent) with an elevation gradient from 1000 m (3,200 ft) to 1100 

m (3,600 ft) over 4.83 km (3 mi) in a southeast to northwest direction (fig. 2). The 

soils are characterized as moderate to shallow, sandy loam derived from ash-fall 

over basaltic colluvium and residuum of weathered tuff and andesite (USDA FS 

2002). The forest type and plant association that best characterizes the study area 

is Pinus ponderosa/Purshia tridentata/Festuca idahoensis (PIPO/PUTR/FEID) 

in which Pseudotsuga menziesii, Calocedrus decurrens, and Juniperus occidentalis are occasional components of the understory (Franklin and Dyrness 1973). 

The most common members of the plant community based on our observations are 

listed in table 1.

Background conditions─

The Green Ridge study site is located within the perimeter of the July 2002 Eyerly 

wildfire, which burned about 9539 ha (23,573 ac) primarily on the Sisters Ranger 

District. The fire was of stand-replacement severity in 90 percent of the dry ponderosa pine plant association, which constituted 5188 ha (12,821 ac) (USDA FS 2004b). 

After the burn, a survey of about 44 km (27 mi) of dozer lines created during fire 

suppression indicated invasive exotics were present on about 70 percent of the surveyed lines (Suna and Van Campen 2003). Areas of high burn severity that lost root 
4

GENERAL TECHNICAL REPORT PNW-GTR-823

Figure 1—Locations of the Pinus ponderosa/Purshia tridentata/Festuca idahoensis (PIPO/PUTR/

FEID) forest type in the central Oregon Cascade Range. Forest Service map with permission from 

Simpson (2007). White arrow shows study site.
5

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Figure 2—Positions of twenty 1-m2 study plots for field seed germination/emergence tests on the Green Ridge site within the boundaries 

of the 2002 Eyerly wildfire. Map, courtesy of the Sisters Ranger District, Deschutes National Forest, includes roads and burn severity: 

1, unburned; 2, low; 3, moderate; 4, high.
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GENERAL TECHNICAL REPORT PNW-GTR-823

Table 1—Most common species observed growing in the vicinity of the 20 test plots 

located in a Pinus ponderosa/Purshia tridentata/Festuca idahoensis plant association at 

Green Ridge, east-side central Oregon Cascade Range

Trees: Forbs (continued)

Calocedrus decurrens (Torr.) Florin Hieracium albiflorum Hook.

Juniperus occidentalis Hook. Lomatium nudicaule (Pursh.) Coult.

Pinus ponderosa var. ponderosa C. Lawson & Rose

Pseudotsuga menziesii (Mirb.) Franco Lomatium triternatum (Pursh.) Coult.

Shrubs: & Rose

Arctostaphylos patula Greene Lotus crassifolius (Benth.) Greene

Ceanothus prostratus Benth. Lupinus spp. L.

Chrysothamnus viscidiflorus (Hook.) Nutt. Microseris spp. D. Don

Purshia tridentata (Pursh) DC. Microsteris gracilis (Hook.) Greene

Forbs: Navarretia divaricata (Torr. ex A. Gray)

Achillea millefolium L. Greene ssp. divaricata

Anaphalis margaritacea L. (Benth.) Penstemon humilis Nutt. ex A. Gray

Apocynum androsaemifolium L. Phacelia heterophylla Pursh

Balsamorhiza careyana A. Gray Senecio triangularis Hook.

Calochortus macrocarpus Dougl. Zigadenus venenosus S. Wats.

Castilleja spp. Mutis ex L. Graminoids:

Clarkia rhomboidea Dougl. ex Hook. Achnatherum thurberianum (Piper)

Claytonia perfoliata Donn ex Willd. Barkworth

Claytonia sibirica L. Bromus tectorum L.

Collinsia parviflora Dougl. ex Lindl. Danthonia unispicata (Thurb.) Munro

Collomia grandiflora Dougl. ex Lindl. ex Macoun

Epilobium angustifolium L. Elymus elymoides (Raf.) Swezey

Epilobium brachycarpum C. Presl. Festuca idahoensis Elmer

Epilobium minutum Lindl. ex Lehm. Koeleria macrantha (Ledeb.) J.A.

Eriogonum umbellatum Torr. Schultes

Eriogonum spp. Michx. Poa bulbosa L.

Eriophyllum lanatum (Pursh) Forbes Poa secunda J. Presl.

Gayophytum diffusum Torr. & A. Gray Pseudoroegneria spicata (Pursh.) A. Love
7

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

stock and seed sources were described as “highly susceptible to invasion by noxious weeds and other nonnative invasives.” Populations of noxious weeds in areas 

disturbed in the fire suppression activities were found to have spread into areas 

previously not infested (USDA FS 2002). The most prevalent of the species were the 

opportunistic, nonnative annual grasses medusahead (Taeniatherum caput-medusae

[L.] Nevski) and cheatgrass (Bromus tectorum), and the forb, spotted knapweed 

(Centaurea maculosa Lam.). Almost all sites were identified as high risk for spread 

by these species (USDA FS 2002). Since then, the spread boundary and density of 

weeds have increased (Suna and Van Campen 2003). 

During the fall of 2002, in accordance with Forest Service guidelines for 

Burned Area Emergency Response (BAER) (FSH 2509-13), the steep, north-facing 

slope north of the study area on Green Ridge was aerially seeded with “sterile” 

winter wheat (Triticum aestivum L. [Madsen]) and annual ryegrass (Lolium perenne

L. ssp. multiflorum (Lam.) Husnot [Gulf]) at a rate of 215 pure live seeds (pls)/m2 

(20 pls/ft2). The seeding extended beyond the slope about 50 m onto the ridgetop. 

Factors in the decision to seed with nonnative grasses were low cost and “lack of 

availability of suitable native species.” The sterile winter wheat and rye formed 

dense patches in 2004–2005 and began encroaching into the study area. Four years 

after the burn in May and June, part of the study area was salvage logged to remove 

dead and severely damaged trees using skyline and helicopter yarding (USDA FS 

2002). 

Throughout most of the burn zone on the top of Green Ridge, Bromus tectorum 

and other nonnative grass species were visible as scattered individuals and small 

patches having migrated upslope from adjacent sagebrush steppe lands. Where 

heavy equipment was used to make fire lanes or for tree removal, the ground was 

scarified to bare mineral soil. Appearing for the first time in these disturbed soils 

were exotic, annual forbs possibly introduced in the commercial grass-seed mix 

(Forcella and Harvey 1983, Miller et al. 1999). However, the fire-opened stands

of pine also increased soil exposure with loss of ground vegetation, which may

have favored the spread of annual grasses such as T. caput-medusa, B. tectorum,

and Vulpia spp. (Merriam et al. 2006, Miller et al. 1999, Mosely et al. 1999,

Wilderman 2003).

Seed Evaluations

Field survey and collection—

Before collecting seeds in 2004, we made a preliminary list of forb and grass species considered appropriate for reintroduction aided by the Deschutes National 

Forest’s species list, a review of published literature, and a preliminary field survey 

of the most common species growing in the PIPO/PUTR/FEID plant association 
8

GENERAL TECHNICAL REPORT PNW-GTR-823

at or near the site. We surveyed for potential seed collection areas and identified 

species that were sufficiently abundant in neighboring unburned areas to furnish 

an adequate amount of seed for the study, then mapped them. The potential seedcollection area comprised about 5180 ha (12,800 ac) on Green Ridge adjacent to and 

including forested lands burned in the Eyerly Fire. To observe species in flower, we 

made several visits to the area in spring and early summer. We confined our seed 

collection areas to the PIPO/PUTR/FEID plant association so that we would not include offsite species. We selected species for collection based on their potential seed 

availability, early establishment and growth, site occupancy, and representation of 

forest type. We chose not to collect species, such as Achillea millefolium, that are 

cosmopolitan and putative increasers after fire and for which there appeared to be 

an adequate seed source (Johnson 1998). These 5 grass and 13 forb species met our 

criteria: Elymus elymoides, Festuca idahoensis, Achnatherum thurberianum, Poa 

secunda, Pseudoroegnaria spicata, Apocynum androsaemifolium, Balsamorhiza 

careyana, Calochortus macrocarpus, Erigeron filifolius (Hook.) Nutt. var. filifolius, 

Eriogonum umbellatum, Eriophyllum lanatum, Linum lewisii, Lomatium triternatum, Lotus crassifolius, Olsynium douglasii (A. Dietr.) E.P. Bicknell, Penstemon 

humilus, Silene douglasii Hook., and Zigadenus venenosus. 

The seeds from plants of locally identified species were hand collected on different dates depending on their phenology of flowering, fruiting, and seed maturation. From July through September 2004, while we collected seeds for field testing, 

we noted condition of fruits or seeds including fullness, maturity, and insect or 

other predation, as well as dates and appearance of fruit or seed maturity. All collected seeds and fruits were placed in labeled paper bags and stored in the shade 

in dry conditions until they were cleaned. Collection procedures for each species 

can be found in the appendix. We also collected individual plants for pressing and 

taxonomic identification at the Oregon State University herbarium. Identification of 

grass species was aided by Dr. Paul Doescher, Department of Rangeland Resources, 

Oregon State University. 

Seeds were not co-mingled with seeds in other collection bags until each was 

carefully examined for insect-infested seeds to avoid cross contamination. For each 

species, we kept collections separate as numbered seed lots if the interval between 

collections was greater than 1 week or if the collection location was separated by 

more than 2.0 km (1.3 mi) until we determined if differences in collection date or 

location affected viability. 

Seed cleaning—

Seeds were collected and cleaned in 2004 and 2005. The seeds were cleaned by 

hand mechanically using screens and air separators tailored to most efficiently clean 
9

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

seeds of each species (Douglas et al. 1997). Slightly different processing equipment was used in each year although the overall approach for each species was 

the same (Harmond et al. 1968). In 2004, we used the seed cleaning facility of the 

USDA Agricultural Research Service laboratory on the Oregon State University 

campus, Corvallis, Oregon. The first stage of the process was to remove awns 

from grass seed and extraneous material from the forb seeds. In 2004, we used 

a Westrup1 brush machine consisting of a mesh wire cylinder and two rotating 

brushes (Barbour 2002). In 2005, at the USDA Forest Service Bend Seed Extractory 

in Bend, Oregon, we used a Clipper air screen separator (USDA FS 2006b). The 

Westrup brush machine or Clipper air screen separator was used in the initial 

cleaning stages on all five grass species and for seeds of Eriophylum lanatum and 

Lomatium triternatum. For seeds of other forbs such as Balsamorhiza careyana, 

fruit or seed heads were crushed by hand or with a crushing boat, and screened. 

The fine chaff and empty seeds were removed by carefully blowing with controlled, 

forced air. Through mechanical cleaning and blowing, we removed almost all of the 

inert matter including broken and empty seeds. The cleaned seeds were placed in 

paper envelopes identified and labeled according to species and source, which were 

then held in cold/dry storage. The specific methods that were applied to seeds of 

each species are reported in the appendix. 

Filled seed—

In 2004, we estimated the amount of filled seed in our collections by sampling 

seeds from our collection bags before samples were mechanically cleaned. For grass 

species, we used back-lighted trays to help determine empty or damaged caryopses. 

We also inspected cut seed using a dissecting microscope to examine the embryo 

and endosperm using the Handbook on Seeds of Browse-Shrubs and Forbs as a 

guide (AOSA 2003a). The percentage of filled seeds differed among lots of the

same species. Some seed lots appeared affected by predators as they had more 

visibly insect-damaged seeds than others. Herbaceous plants are known to vary 

spatially and temporally in seed production and abundance (Apfelbaum et al. 1997). 

Estimating this variability would be useful for calculating how much collecting

effort is needed to acquire a given amount of good seed. 

Because fecundity of a plant species greatly influences the availability of 

seeds, determining intra-specific variation in filled seed would aid in developing a 

seed collection strategy. The percentage of filled seed is also a measure of a species’ reproductive fitness. In 2005, we introduced a sampling scheme so that we 

1

 The use of trade or firm names in this publication is for reader information and does not 

imply endorsement by the U.S. Department of Agriculture of any product or service.
10

GENERAL TECHNICAL REPORT PNW-GTR-823

could calculate percentage of filled seed from a known number of fruiting units. 

To ensure that the range of environmental adaptation to the site was genetically 

represented, we stratified the collection area into five subareas for collecting fruits 

of 14 species in a stratified random design. We gathered fruits of each of 14 species 

from four randomly selected plants in each of the subareas. All seeds were carefully 

removed from the seed head or fruit and counted. We recorded filled, empty, and 

damaged seed from individual or multiple fruits, depending on the species, using 

the method previously described. All caryopses of the grasses in the panicle or 

spike of a single stem were counted. Seed heads were the fruit unit for species of 

the Asteraceae family, and the umbel for Eriogonum umbellatum (3 to 8 seed heads/

umbel) and Lomatium triternatum (9 to 16 umbellate seed “heads” of a compound 

umbel). For Linum lewisii, Silene douglasii, and Penstemon humilis, as well as the 

liliaceous monocots, a capsule was the fruiting unit. 

The filled-seed data were analyzed by analysis of variance (ANOVA). Each 

species was analyzed independently. For five of the species, filled-seed data that 

did not meet the assumptions for ANOVA were analyzed by the nonparametric 

Kruskal-Wallis (1952) one-way analysis of variance, (the Kruskal-Wallis statistic 

H and the ANOVA statistic F agreed at P ≤ 0.05 level of confidence). Because the 

medians of the species nonparametrically tested for variance were close in value to 

the means, means are shown for all species in table 2.

Variability in filled seed was high among the fruits within each species in 

2005 and greater among sampled individuals of a species within each subarea than 

among subareas for most species. Despite the high variability among individuals, a significant difference in average filled seeds (P < 0.05) among subareas 

was detected in L. triternatum, S. douglasii, Poa secunda, and Pseudoroegnaria 

spicata. The causes of the differences were not identified, but spatial variation in 

fecundity within a large population or seed collection area has implications for 

developing a seed collection strategy that seeks to gather not only quantity but as 

much quality seed as possible. 

Although the mean filled-seed rate of many species differed between years 

(table 2), data were not compared statistically, because in 2004 the percentage of 

filled seed was calculated on seeds drawn from seed lots representing a variable 

number of plants. In 2005, seeds were collected from fruiting units on only four 

randomly selected plants per subarea. However, the seeds both years came from 

the same seed collecting area. In 2004, chaff had been removed from the seeds 

of Balsamorhiza careyana, L. lewisii and S. douglasii by hand screening before a 

sample was drawn from the bags; nevertheless, the filled-seed rate of L. lewisii both 

years was 100 percent, consistent with high percentages of germination reported by 
11

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Table 2—Filled-seed percentage of seeds collected in 2004 

(pooled seed) and 2005 (directly from plants) of 5 grasses and 

13 forbs growing in an approximately 26-km2 (10-mi2) area 

at the Green Ridge study site in the east-side central Oregon 

Cascade Range 

Species 2004 2005

 Percent

Grasses:

Achnatherum thurberianum 60.0 61.6

Elymus elymoides 75.0 81.8

Festuca idahoensis 47.0 40.5

Poa secunda 35.0 33.2

Pseudoroegnaria spicata 33.3 22.6

Forbs:

Apocynum androsaemifolium 54.0 N.d.

Balsamorhiza careyanaa 48.9 8.7

Calohortus macrocarpus 90.0 47.0

Erigeron filifolius 45.0 11.6

Eriogonum umbellatum 71.7 17.3

Eriophyllum lanatum 71.0 57.8

Linum lewisii a 100.0 100.0

Lomatium triternatum 73.3 86.5

Lotus crassifolius 73.3 60.3

Olsynium douglasii 88.9 N.d.

Penstemon humilis 83.3 N.d.

Silene douglasii a 100.0 78.0

Zigadenus venenosus 82.2 N.d.

Note: For 2004 seeds, Number of lots tested ranged from 1 to 6; for 2005, N = 5; 

N.d. = no data.

a.

Seeds in 2004 were previously hand cleaned.

Meyer and Kitchen (1994). The filled-seed rate of B. careyana was low in 2004 and 

was much lower in 2005 (table 2). The seed heads of B. careyana plants collected in 

2005 were fewer in number, frequently appeared damaged, and were smaller than 

those collected in 2004 indicating that the reduction in filled seed probably was not 

due to hand cleaning the seeds. In 2005, ungulates browsed the fruiting stalks of 

Calochortus macrocarpus; from the appearance of the browsed plants, the browsers 

selected taller stems bearing larger capsules. We noticed smaller plants remained 

with smaller fruit having fewer filled seeds than fruit in 2004. Other forb species 

also appeared to have lower filled-seed rates in 2005 for which we have no explanation. However, reported differences in rate of filled seed between years have been 

related to corresponding differences between years in temperature and precipitation 

during seed development (Valencia-Diaz and Montaña 2005). 

Seed collecting in the wild would be more effective if estimation of seed

collection time and effort included not only spatial distribution and density of 
12

GENERAL TECHNICAL REPORT PNW-GTR-823

flowering plants, but also the plant’s fecundity or rate of seed production. Being 

able to estimate seed productivity would increase efficiency by providing a better 

estimate of how many flowering plants are needed for seed. Parameters that may 

help in estimating seed productivity are ratio of fruit-to-flower, total number of 

seeds, and percentage of filled seeds per individual. If plants in a collection area 

have a high yield of seed, then collection intensity might be reduced. In addition, if 

plant fecundity is found to differ within a large collection area, it is important that 

the collection area be appropriately represented. It is safe to suggest that the interplay of biological, genetic, and environmental factors that influence seed production 

may also produce ecotypic variation that is spatially distributed in seed traits among 

populations or colonies (Erickson et al. 2004, Linhart 1995). 

Seed weight—

As the number of seeds per unit weight is influenced by a seed’s moisture content, 

we calculated the moisture content of seeds at time of weighing. Collected seeds 

were left in open paper bags in the laboratory for 1 week before they were weighed 

to ensure that seeds were sufficiently dry and their weight was stable. To determine 

moisture content, a representative sample of seeds was weighed, dried in a laboratory oven at 65 o

C (149 oF) for 24 h, equilibrated with room temperature in a desiccator, then reweighed. This procedure was repeated for another 24 h at a drying 

temperature of 105 oC (221 oF). After the second drying, relative moisture content 

was calculated on a wet-weight basis. Seed number per unit weight was calculated 

for each species using cleaned seeds having moisture content ranging from 5.8 to 

9.9 percent (table 3). 

We determined number of seeds per kilogram (pound) for each species by 

calculating the mean weight in grams of three replicates of 50, 100, and 200 randomly sampled seeds with weight recorded to 0.0001 g. Mean weight was linearly 

regressed against the counted seeds to generate the number of seeds per unit weight 

(grams). The coefficient of variation (r2

) of each regression was > 0.99 for seeds of 

every species. The number of seeds per kilogram and per pound is shown in table 3. 

For some species, the rate deviated from published data (Hassell et al. 1996, Lambert 2005, Monsen and Stevens 2004). For example, the mean number of seeds per 

pound of L. lewisii seeds that were collected at Green Ridge was 152,095, but

as many as 278,000 to 420,000 seeds per pound were reported in Seeding Rate

Statistics for Native and Introduced Species by Hassell et al. (1996). Such discrepancies may be due to differences in purity of the seed lot and moisture content of 

the seeds, resources for seed development, seed predation, or genetic-based differences among varieties in seed size or mass (Cavers and Steel 1984, Thompson and 
13

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Table 3—Number per unit weight of cleaned, filled seeds of 18 native plant species at the 

relative moisture content indicated (ambient temperature 22 to 25 oC)

 Seed Seed

Species Seeds/kg Seeds/lb moisture TZ lots

No. No. % % No.

Grasses:

Achnatherum thurberianum 485,950 220,886 9.9 92 3

Elymus elymoides 190,440 86,564 9.7 92 2

Festuca idahoensis 676,050 307,295 9.2 83 3

Poa secunda 1,655,800 752,182 8.8 69 2

Pseudoroegneria spicata 267,790 121,723 9.3 87 2

Forbs:

Apocynum androsaemifolium 2,684,700 1,220,318 — 55 1

Balsamorhiza careyana 93,130 42,332 7.8 79 2

Calochortus macrocarpus 377,010 171,368 − 86 1

Erigeron filifolius 5,301,900 2,409,955 7.2 85 2

Eriogonum umbellatum 291,000 132,245 8.8 73 2

Eriophyllum lanatum 1,387,900 630,864 5.6 59 2

Linum lewisii 334,610 152,095 5.9 97 1

Lomatium triternatum 145,160 65,982 7.9 77 1

Lotus crassifolius 88,230 40,105 7.9 95 2

Olsynium douglasii 293,460 133,391 — 79 1

Penstemon humilis 4,822,100 2,191,864 — 88 1

Silene douglasii 1,523, 700 692,591 9.3 90 2

Zigadenus venenosus 285,770 129,895 — 86 2

Note: Seeds were tested for viability using tetrazolium (TZ) at Oregon State University Seed Laboratory. 

Percentage of viability shown is the mean of the lots unless a single lot was used.

Pellmyr 1989, Tyson 1989). For example, the Linum cultivar “Appar” has significantly lighter seeds than interior northwestern ecotypes of the native L. lewisii

(Pendleton et al. 2008).

Physiological tests—

Approximately 200 cleaned seeds from collections of each species were tested for 

viability at the Oregon State University Seed Testing Laboratory, Corvallis, Oregon, 

using Association of Official Seed Analysts (AOSA) protocols (AOSA 2003b, Peters 

2000). The test included quantification of filled or abnormal seed, and a chemical 

test for metabolic activity by means of tetrazolium (TZ) salts color analysis (Peters 

2000). A viability test was run on each lot and is presented as the mean percentage 

of the lots that were pooled for use in the in vitro germination tests as well as in the 

field evaluation (table 3).

Seeds in long-term storage should be stored at low temperatures and at a 

sufficiently low moisture content to maintain dormancy, hold respiration to a 

minimum, and inhibit microbial activity (Iriondo and Perez 1999, Jorgensen and 
14

GENERAL TECHNICAL REPORT PNW-GTR-823

Wilson 2004, Young and Young 1986). For approximately 6 months, seeds stored 

dry in paper bags were kept in a walk-in cooler. Seeds of grasses were not stratified. In mid January, seeds of forbs receiving 10-week stratification were placed 

in cheesecloth, soaked 24 h under running water in mesh bags, and stored in filter 

paper in a walk-in cooler for 10 weeks. Although the thermostat in the cooler was 

set for temperatures that ranged from 2 to 4 oC (36 to 39 oF), the temperatures after 

the first week were found to be ranging from approximately 4 to 6 oC (39 to 43 oF). 

The seeds of Eriophylum lanatum, Eriogonum umbellatum, Silene douglasii, and 

Zigadenus venenosus germinated in the cooler with some appearing moldy. Many 

of the ungerminated seeds of Apocynum androsaemifolium were also moldy (74 

percent). The seeds were moved to a different cooler in which the temperature was 

3.9 oC ± 1o (38.0 oF ± 1o); but the germination test was compromised for these species. Five replicates of 50 seeds each for each species that could be tested, including 

the unstratified grass seeds, were rinsed, placed on moistened filter paper in a 

labeled petri dish, and placed in a growth chamber set to a 12-h, day/night thermoperiod of 18/10 o

C (64/50 oF). Seeds were counted every day or every 2 days for up 

to 10 weeks. Seeds that germinated and acquired mold were recorded and removed. 

Because Lotus crassifolius is a leguminous species with a putative impermeable 

seed coat, different treatments were applied including stratification with a 48- or 

24-h pre-soak, and with light scarification (using sandpaper) or no scarification. 

The no-stratification treatment had a 48-h pre-soak and scarification only. Each 

treatment replicated five times was applied to seeds of L. crassifolius that were 

germinated as described above. The treatments were statistically tested for treatment differences by ANOVA. 

The mean germination percentage of unstratified seeds of L. crassifolius with 

48-h soak and scarification was significantly lower (P < 0.05) than the germination of stratified seeds with additional soak and scarification treatments. Among 

the stratified seeds, the longer (48-h) soak and scarification significantly improved 

germination (table 4). Our results agreed with those reported by the USDA Natural 

Resources Conservation Service, Corvallis Plant Materials Center (Flessner and 

Darris 2001). The mean germination percentage of all grass species was 75.9 percent (Poa secunda was not included in the test). However, seed germination rates

of stratified seeds of the forbs were lower than their potential to germinate as 

indicated by the viability tests (table 3, table 4). 

Some species’ germination requirements apparently were not met by the

procedures we used. For example, none of the Linum lewisii seeds germinated

even though filled-seed and viability percentages were high. Seed germination might have improved under lower temperatures and an 8-h day/16-h night, 
15

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Table 4—Germination of grass and forb seeds collected from Green Ridge, 

Deschutes National Forest, with or without 10-week stratification 

Species	 Stratification	 Germination	 Mold

 – – – Percent – – –

Grasses:

Achnatherum thurberianum + 64.8 8.0

Elymus elymoides − 82.8 7.2

Festuca idahoensis − 80.8 9.2

Pseudoroegneria spicata − 75.2 9.6

Forbs:

Apocynum androsaemifolium + 28.0 74.7

Balsamorhiza careyana + 9.6 8.8

Erigeron filifolius + 35.3 16.0

Eriogonum umbellatum – 37.2 42.4

Linum lewisii + 0.0 1.8

Lomatium triternatum + 16.0 1.5

Lotus crassifolius

Scarification, 48 h soak − 0.4a 2.0

No scarification, 48 h soak + 29.6b 1.2

Scarification, 48 h soak + 43.2c 0.8

No scarification, 24 h soak + 29.6b 0.4

Scarification, 24 h soak + 32.8bc 0.4

Note: Seeds were germinated in the laboratory under standard light and temperature. Additional 

treatments were applied to seeds of Lotus crassifolius only. Letters indicate significant 

differences among treatments at P ≤ 0.05, N = 5.

which mimics the short day length of spring/fall when most seeds of these species naturally germinate (Beckstead et al. 1995, Goodwin et al. 1996, Young and 

Evans 1979). Drake et al. (1998) reported that outdoor germination under natural 

conditions appeared to improve germination, which suggests that test conditions 

more closely approximating those of the seeds’ native conditions may improve test 

results. 

For optimal results, in vitro seed germination test conditions at a minimum 

should be species specific and ideally based on the physiological seed and dormancy requirements that may occur among different ecotypes. Seed dormancy and 

germination requirements have been found to differ not only among species but 

among ecotypes and populations within a species (Doescher et al. 1985, Erickson 

et al. 2004, Goodwin et al. 1996, Meyer and Kitchen 1994). The germination of L. 

lewisii seeds from the intermountain West ranged from 0 to 100 percent depending on their origins, dormancy requirements, ability to after-ripen, and genotype 

(Jorgensen and Wilson 2004, Meyer and Kitchen 1994). Dormancy and initiation 

of seed germination also may be influenced by elevation, latitude, and climatic 

patterns of the population’s origins (Beckstead et al. 1995, Cavieres and Arroyo 

2000). Seeds of perennial, vernal herbs and grasses able to germinate in cold soil 
16

GENERAL TECHNICAL REPORT PNW-GTR-823

at elevations of about 1000 m (3,280 ft) or lower may require shorter periods of 

stratification than species adapted to higher elevations (Cavieres and Arroyo 2000). 

The native grasses Elymus elymoides, Festuca idahoensis, Poa secunda, and Pseudoroegnaria spicata adapted to the elevation and climate of Green Ridge or other 

similar environments in the ponderosa pine zone east of the Cascades summit may 

not require stratification; their germination phenology at midelevations or lower 

may be dictated more by precipitation patterns (Beckstead et al. 1995, Goodwin et 

al. 1995). 

Species’ Performance on Site

Site preparation and sowing—

In September 2004, the study plots were located on the easternmost extension of 

Green Ridge within the southeastern edge of the Eyerly Fire boundary. Twenty 

plots were installed transecting the southern burn boundary and spanning about

5 km or 3 mi (fig. 2). Each 1-m2

 plot was located 50 m from the road and a minimum distance of 150 m from each other. Part of the 5-km transect intercepted an 

unburned area from which plots were excluded.

In each 1-m2 plot, sixteen 15- by 15-cm (6- by 6-in) and two 4- by 60-cm (2- by 

24-in) subplots were prepared for seeding by clearing off thatch and debris, and 

lightly raking the surface. Four furrows about 15 cm long and 4 cm apart were 

prepared for each of the 16 subplots, and a single furrow about 60 cm long was 

prepared for the two additional species. Each long subplot had a minimum of 5 cm 

(2 in) between its furrow and that of any other subplot so that no seeded furrow was 

closer than 5 cm from another, within or between species. The species were randomly assigned a subplot in each of the 20 plots with the exception of Calochortus 

macrocarpus and Penstemon humilis, which were randomly assigned to one of the 

4- by 60-cm plots.

Where there was more than one seed lot available, two or more lots of each 

species were combined equally by weight based on lot size, percentage purity, and 

TZ test results. Fifty seeds of each species having relatively large seeds and 100 

seeds of each grass species and forb species having smaller seeds were counted and 

replicated 20 times. The seeds were sown individually by hand in late September 

at a depth of 1.0 to 1.5 cm (0.4 to 0.6 in) depending on seed size of the species. 

Soil was smoothed over the seeds and gently tamped down. We used no mulch for 

cover; however, chicken wire was firmly secured over the plots to protect the seeds 

from large animal disturbance (fig. 3A). The plots were marked at each corner and 

oriented toward the north for consistent reference and relocation. 
17

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Figure 3—(A) One of twenty study plots installed at Green Ridge, Deschutes National Forest to evaluate native plant seed germination, 

seedling emergence, and survival. (B) Eriogonum umbellatum germinant emerging in early March with anthocyanin pigment visible 

on hypocotyl and cotyledon. (C) Frost heaving caused grass seeds sown 1.0 to 1.5 cm below ground to germinate on the surface of the 

soil. (D) Soil surface of plot 2 that reached temperatures > 50 o

C; the herb Navarretia divaricata ssp. divaricata adapted to survive those 

conditions. (E) A Lotus crassifolius seedling that has been predated by insect larvae. (F) A study plot with vegetative cover consisting 

primarily of the invasive annual grass Bromus tectorum.

We measured relative light over the plot using a LI-COR LAI-2000 Plant 

Canopy Analyzer (LI-COR Inc. Lincoln, NE). The plant canopy analyzer estimates 

exposure of plot relative to full irradiance by calculating a ratio of nonintercepted 

diffused light (DIFN) measured on plot points to a fixed point receiving full light. 

Five calculations of DIFN were averaged from filtered solar irradiance readings 

1.0 m (3.3 ft) above ground at plot center and at each plot corner. We installed 

sensors for collecting microclimate data (models GPSE 301 203, A.R. Harris Ltd. 
18

GENERAL TECHNICAL REPORT PNW-GTR-823

Christchurch, New Zealand) near plots that would best represent the range of 

moisture and temperatures in the transect. The sensors were positioned to measure 

air temperature and relative humidity 50 cm above the ground and soil temperature 

at rooting level 3.0 to 4.0 cm (1.2 to 1.6 in) below ground. Before the plots were 

prepared for sowing, we recorded moss, forb, and grass cover and soil exposure. We 

also recorded the most commonly occurring plants that were present in the plot and 

up to 3 m outside the plot perimeter, and recorded the presence of Bromus tectorum

outside and within the plot.

Emergence of shoots or cotyledons was used as a measure of successful seed 

germination. Because vernal herbs only grow and reproduce in the spring, we recorded emergence beginning in February 2005. Cumulative emergence was tallied 

for each species in each of the 18 subplots 20 times at intervals of 3 to 4 weeks 

through May 2005 when there was no visible new emergence. We calculated mean 

germination of each species as the mean of the highest number of emergent seedlings recorded in each of the 20 plots from February through April 2005 (N = 20). 

Mean percentage of survival was calculated from the recorded number of living 

seedlings in May and June 2005, and May 2006. When seedlings were of sufficient 

height (≥ 1 cm), we also measured the length of the five longest leaves or shoots 

of selected individuals in each subplot; otherwise we noted if they were < 1 cm. In 

addition, we recorded the percentage of exposed soil, moss, and vegetative cover, 

and separately, cover of the 18 study species in the plots. We also recorded presence 

of invasive species, and noted visible predation, disease, or injury. Data in May 

2006 were taken under drier conditions than May 2005 (Oregon Climate Service 

2009). Leaves, especially of the monocots, had begun senescing in May 2006, so 

percentage of their cover may have been underestimated. 

Statistical analysis to compare differences between years for each species was 

by paired t-test on repeated measures for survival and cover. Where assumptions 

of equal variance were not met, the nonparametric Mann-Whitney-Wilcoxon test of 

differences between medians was used (α = 0.05). Regression analysis was used to 

examine relations between variables.

Field environment—

Diurnal soil temperatures in February and March fluctuated above and below freezing. Soil temperature at night near the surface and within the rooting zone was 

lower than if there had been an insulating snow layer. However, the anthocyanic 

pigments visible in the cotyledons and hypocotyls (fig. 3B) suggest they are cold tolerant if not freezing tolerant (Close et al. 2004, McKown et al. 1996). Lack of snow 

cover also promoted cycles of freeze and thaw in the soil that cause “frost heaving,” 
19

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

a dynamic microtopography that, depending upon root length and seed size or position, either buries, shelters, or exposes germinating seeds to temperature extremes. 

This phenomenon was particularly evident in plots with little canopy or vegetative 

cover (fig. 3C). Frost heaving contributed to reducing the rate of emergence and 

survival of some of the small-seeded and grass species, as dead germinants were 

observed on the soil surface. However, their mortality in relation to frost-heaving 

could not be quantified.

The DIFN on the 20 plots ranged from 0.52 to 0.96 on plots with moderate 

shade to near total exposure. The monthly mean soil temperatures of plots highly 

exposed to solar irradiance were higher in spring and summer than those of the 

more shaded plots. For example, the fully exposed plot 2 (figs. 4C, 3D) had greater 

fluctuations in soil temperature than the partially shaded plot 18 (fig. 4B). By July, 

the mean maximum soil temperature in exposed plot 2 exceeded 50 oC and was 

almost 10 degrees higher than the shaded plot 18 (fig. 4 C, D). Soil surface temperatures > 50 oC can be lethal to newly emergent seedlings and may have contributed 

to high mortality in those plots (Wickens 1998). Note that the dominant species on 

Figure 4—Mean monthly air and soil temperatures from the high, low, and average diurnal temperatures taken by data loggers from 

February 2005 through May 2006 installed adjacent to plot 2 (A,C) and plot 18 (B,D), which had different levels of direct sunlight, 

(nonintercepted diffuse light [DIFN] = 0.94 and 0.69, respectively).

 Maximum

∆ Average

 Minimum
20

GENERAL TECHNICAL REPORT PNW-GTR-823

the otherwise depauperate plot 2 was Navarretia divaricata ssp. divaricata, an herb 

of the dry West structurally adapted to avoid tissue damage from lethal soil surface 

temperatures in semiarid climate (fig. 3D).

The mean percentage of exposed soil and cover of moss and herbaceous vegetation on the 20 plots differed temporally as well as spatially. Nonvegetated soil 

declined from 78 percent in 2004 to 65 percent in 2006 as moss and herbaceous 

cover correspondingly increased. Moss cover increased from 3 percent in 2004, 

(range, 0 to 15 percent) to 23 percent in 2006 (range, 0 to 80 percent). There was no 

linear relation between percentage of seedling emergence on plots and moss cover, 

and no direct relation between amount of tree canopy as indexed by DIFN and moss 

cover. Postfire recovery of moss appeared to depend less on tree shade than on soil 

moisture and the micro-canopy afforded by herbaceous plants and litter. Shade, 

moisture, and soil temperature appeared to interact in early spring. Although 

shaded plots retained moisture on the soil surface longer than those plots exposed to

greater solar irradiance, from February through April (when moisture was not limiting) their maximum soil temperatures were lower, which may have slowed seed 

germination and growth (e.g., max soil temperatures of Plots 2 and 18 in figure 4).

Seedling emergence, growth, and survival—

On February 10, 2005, the mean air temperature from 1000 to 1500 hours was 8 o

C

(46 oF), and soil temperatures at rooting level ranged from -2.0 to 0.5 oC (28.4 to 

32.9 oF). Because the test plants are vernal species, we expected early seed germination; nevertheless, we were surprised that seeds of 10 of the 18 species had 

already germinated despite snow covering some of the plots. Mean emergence 

of four grass species, Elymus elymoides, Festuca idahoensis, Poa secunda, and 

Pseudoroegnaria spicata, in February was 45.0 percent. Leaves of these grasses 

averaged about 4 cm in length indicating seeds had germinated in the fall. Seeds

of the grasses P. secunda, E. elymoides and P. spicata have been described as nondormant (Beckstead et al. 1995, Darris 2007). Goodwin et al. (1995) noted that 

seeds of F. idahoensis could be partially dormant as some germinated in fall and 

some in spring. Seeds of Achnatherum thurberianum, however, were apparently 

dormant when sown, as there was no visible emergence until mid March. 

In February, emergence also was evident by the appearance of cotyledons of 

six forb species, Balsamorhiza careyana, Calochortus macrocarpus, Erigeron 

filifolius, Eriogonum umbellatum, Lomatium triternatum and Zigadenus venenosus.

In early March, we observed the emergence of Eriophyllum lanatum, Linum lewisii, 

Olsynium douglasii, Penstemon humilis, and Silene oreganum, and in early April, 

the emergence of Apocynum androsaemifolium and Lotus crassifolius. Mean 
21

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

percentage germination of the 18 species collectively was 36.9 percent; of the 5 

grasses, 46.3 percent; and 13 forbs, 33.3 percent. Mean germination of the lilioid 

monocots (C. macrocarpus, O. douglasii, and Z. venenosus) was 47.9 percent (table 

5). The field germination of B. careyana, L. lewisii, and L. triternatum were much 

higher than their in vitro germination tests, confirming that the ex situ stratification and germination environment including light and temperature did not provide 

optimal germination conditions for these species. The germination of A. androsaemifolium was very low (2.5 percent) and no survivors were found in 2006. The 

germination of E. filifolius and P. humilis in 2006 was also low (< 20 percent). 

Seedling survival as a percentage of seeds sown, calculated for each field 

visit, indicated that by late May, recruitment had virtually ceased while attrition 

increased. The mean survival of all species combined was 26.9 percent in

April 2005, declined to 20.3 percent in June, and continued declining to 13.3 percent in May 2006 or half of the survival rate in April 2005. The mean survival

calculated for each species tested for differences between years with a paired t-test 

(N = 20) was significantly lower in 2006 than 2005 (P < 0.05) with the exception 

Table 5—Germination rate based on max germination from February through April 2005 and percentage of 

survival and cover in 2005 and 2006 of 18 native species from seeds sown in fall 2004 within the Eyerly Fire 

boundary on Green Ridge

Germination Survival Cover Height

Species	 Mean	 (± sd)	 2005	 2006	 2005	 2006	 2005	 2006

– – – – – – – – – – – – – Percent – – – – – – – – – – – – – Centimeters

Grasses:

Achnatherum thurberianum 32.8 18.3 29.0 13.4* 4.6 1.6* 6.0 7.1

Elymus elymoides 62.8 3.1 46.2 15.3* 12.6 12.9 6.9 9.2

Festuca idahoensis 48.1 19.2 30.5 9.5* 9.0 11.4 5.0 7.2

Poa secunda 46.3 19.7 26.1 15.8* 6.2 5.8 2.2 3.7*

Pseudoroegnaria spicata 41.6 11.9 25.8 5.7* 4.7 3.9 8.2 8.3

Forbs:

Apocynum androsaemifolium 2.5 5.7 1.2 0.0* 0.0 0.0 <1 0.0

Balsamorhiza careyana 55.8 6.7 45.2 34.7* 14.9 17.9 4.8 6.5

Calochortus macrocarpus 54.7 14.0 37.0 24.7* 2.1 1.1 NA 6.0

Erigeron filifolius 11.0 12.0 1.4 1.2 0.1 0.4 <1 <1

Eriogonum umbellatum 34.5 19.9 21.6 11.3* 3.1 7.4 <1 2.3

Eriophyllum lanatum 16.9 11.2 13.9 5.9* 6.8 6.1 <1 3.1

Linum lewisii 34.3 14.6 29.4 25.8 4.4 12.7 3.1 8.0

Lomatium triternatum 70.8 21.6 45.1 35.8* 5.6 6.1 5.8 10.1*

Lotus crassifolius 22.4 11.9 21.7 1.1* 5.5 0.4* 1.8 2.3

Olsynium douglasii 45.0 17.2 29.8 22.3 4.2 1.8* NA 6.2

Penstemon humilis 18.3 15.3 10.6 0.8* 0.5 0.2 <1 <1

Silene douglasii 23.1 14.9 12.7 4.1* 2.2 1.1 <1 2.7

Zigadenus venenosus 44.2 18.4 32.7 25.6* 3.8 2.4 NA 5.8

Note: Mean height of grasses and forbs were calculated from measurements of five sampled individuals, or all individuals if five or 

fewer were in plot. Significant difference between years shown with an asterisk (*) (p < 0.05) N = 20. 
22

GENERAL TECHNICAL REPORT PNW-GTR-823

of E. filifolius, which had extremely low survival in 2005, and L. lewisii, which 

recruited new seedlings in 2006 (table 5). For each species, the trend in percentage 

of surviving seedlings from February through May is shown graphically in the 

appendix. 

Generally, those species with a high percentage of germination had proportionally greater survival than those with low germination. The combination of 

germination and survival may be a good indicator of reproductive fitness in this 

environment. The percentage germination of Balsamorhiza careyana, Calochortus 

macrocarpus, Linum lewisii, Lomatium triternatum, Olsynium douglasii, and 

Zigadenus venenosus was higher than 33.3 percent (mean for all forbs), and their 

mean survival rate in 2006 was greater than 20 percent. In addition, the presence 

of B. careyana, L. lewisii, and Z. venenosus in 2006 on all plots including plot 2, 

the harshest plot that supported the least herbaceous cover, suggests that seedlings 

of these species’ fitness includes being broadly adapted to a range of conditions 

at the Green Ridge site. It should be noted, however, that even if percentages of 

germination appear low, in the wild, the implications for judging seeding success 

are different than in an agricultural setting. A rate of 20 percent emergence for 50 

seeds sown in > 1/16th of a 1-m2 plot represents potential for 10 individual plants to 

grow in that space. For a large, long-lived herb like B. careyana that would be an 

excessive density. 

Measuring survival may be confounded by differences in dormancy of seeds of 

species adapted to the variable environment of a transitional forest/steppe interface. 

For example, we observed in 2006 a new cohort of L. lewisii seedlings. These 

seedlings averaged about four per plot and increased survival of L. lewisii from

20.3 percent to 25.8 percent. This carryover of seed viability and dormancy of this 

species is not unique to the Green Ridge site as it was previously reported for L. 

lewisii accessions at different elevations in Utah (Meyer and Kitchen 1994.)

Invertebrate herbivory of the germinants was first apparent in March 2005 

when cotyledons were expanding. The species that most commonly had visible 

signs of herbivory during the cotyledon stage in March were E. umbellatum,

B. careyana, and L. triternatum. In April, signs of herbivory were also visible 

on L. lewisii, S. douglasii, and L. crassifolius cotyledons. Insect predation of L. 

crassifolius was particularly severe in damaging cotyledons, shoots, and emerging 

leaves (fig. 3E), resulting in a major decrease in survival and cover between 2005 

and 2006 (table 5). The overall rate of emergence was about 30 percent in mid 

March with much of the early mortality from frost heaving. The grass seedlings in 

plot 2 with little vegetation and high solar exposure died from desiccation and lethal 
23

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

temperatures because many of the seeds were displaced to the soil surface (figs. 3C, 

4A). This may be because of the horizontal placement of the seeds that are normally 

“drilled” vertically into the soil when they disperse naturally with awns intact. The 

decline in survival from April through June 2005 appeared generally attributable to 

high soil surface temperatures, herbivory, and competition by annual exotic grasses. 

Because of episodic rainstorms through May 2005, moisture was retained in the 

soil-plant interface on the more vegetated plots resulting in the appearance of a 

botrytis-like mold on some of the seedlings detected only in one visit in early April. 

By early April 2005, the dicotyledonous forbs were growing stems and true 

leaves. Additional leaves of the lilioid monocots (C. macrocarpa, O. douglasii, Z. 

venenosus) elongated in the following months of the growing season. By late May, 

leaf growth of the three species had slowed or stopped, and by June 2005, the leaves 

of many individuals had begun senescing particularly on the more exposed plots. 

Although most of the plants remained vegetative and immature in 2006, leaf growth 

of forbs continued (table 5). A proportion of L. lewisii (20 percent), L. triternatum

(10 percent), and E. lanatum (10 percent) produced stems bearing buds and flowers 

indicating that they had grown to maturity within 2 years. Although the leaves of 

all the monocots increased in length between 2005 and 2006, none of them had 

grown to maturity or acquired enough resources to develop a flowering stem. 

Growth of dicot species also resulted in increasing cover. Eriophylum lanatum grew 

little in height but increased in lateral spread (table 5).

In February 2005, the leaves of the fall-emergent grasses E. elymoides, F. 

idahoensis, P. spicata, and P. secunda had lengthened to about 2 to 4 cm (0.8 to 

1.6 in) (fig. 5). The leaves of A. thurberianum did not emerge until after February. 

However, leaf growth was rapid so that by May, mean leaf length was 6 cm. During the same period, leaves of P. secunda grew very little. Leaves grew in length 

between 2005 and 2006, but by the end of the second growing season, mean leaf 

length of P. secunda, a short-tufted grass, was 3.7 cm, or less than half the mean 

length of the four other grasses (fig. 5, table 5). Maturation apparently takes several 

years, as leaves were all basal and no grasses had developed flowering shoots. In 

2006, the leaves of the grasses continued to increase in length, but the plants also 

increased biomass by sprouting new shoots (tillering). Cover of A. thurberianum

was significantly lower in 2006 than in 2005, whereas the cover of the other grasses 

was not significantly different between the two years (table 5). The cover data 

however do not show the real increase in biomass and cover of the individual plants 

because the same amount of cover in 2006 was produced by significantly fewer 

surviving seedlings (table 5). 
24

GENERAL TECHNICAL REPORT PNW-GTR-823

The amount of aerial spread is what determines cover but does not really 

indicate fully the growth or level of occupancy of the plant. Forbs are a heterogeneous mixture of growth forms having both vertical and horizontal components 

of occupancy including that which takes place below ground. Above the ground, 

occupancy may expand by a plant’s having vertically and horizontally spreading 

leaves, or a branching growth form, as for example, B. careyana and L. lewisii, 

respectively. Others grow primarily vertically with one elongating stem and slender 

leaves like L. triternatum or with usually two slender leaves that elongate like the 

lilioid monocots C. macrocarpus, O. douglasii, and Z. venenosus. For these species, cover is proportionally low relative to biomass. In contrast, vegetative spread 

by branching and horizontal growth is best represented by E. lanatum, which 

increased in cover from 3.1 percent to 7.4 percent between 2005 and 2006 although 

the percentage of survivors declined from 13.9 to 5.9 during the same period (table 

5). This mixture of growth forms for a suite of herbs that all grow and flower during the same months is one way in which species optimize the vertical and horizontal space that they share.

Vegetative dynamics—

In 2006, the mean herbaceous cover of the 20 plots was 17.6 percent. Despite a decrease in survival of 46 percent, the mean cover of the 18 study species considered 

collectively on the 20 plots did not change significantly from 2005 to 2006 (5.0 and 

5.1, respectively). The study species made up 29 percent of the herbaceous cover, 

Figure 5—Mean leaf length of five native grass species over the first two growing seasons. Seeds were sown in late September 2004 in twenty 1-m2

 plots at the Green Ridge 

site in the east-side central Oregon Cascade Range. 
25

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

and the nonnative grasses having a mean cover of 5.4 percent composed 31 percent.

However, in plots where annual, nonnative grasses were most dense and contributed

more than 75 percent of the herbaceous cover, sown native species contributed less 

than 8 percent. The relative cover of the study species was negatively related to 

invasive cover (r 2 = 0.77, p < 0.001) in an exponential model, suggesting that the 

density of the annual nonnative grasses interfered significantly with the growth and 

spread of the study species (fig. 6).

Between 2004 and 2006, the invasive annual grass, Bromus tectorum, increased 

in abundance throughout the burned site where the 20-plot transect was located (fig. 

3F). Although B. tectorum may have germinated in the fall, we did not detect emergence of B. tectorum until early March. Bromus tectorum commonly germinates in 

early spring when soils have high moisture content and are warmed (Martens et al. 

1994, Roundy et al. 2007). Patches of Vulpia myuros (L.) C.C. Gmel., a nonnative 

grass that increases after fire (Howard 2006), also appeared in or near the plots. 

Although competition for resources by established native perennial species may 

inhibit B. tectorum (Chambers et al. 2007), under other conditions of disturbance, 

B. tectorum can outcompete native perennial species newly emergent from seed and 

inhibit their growth and survival (Goodwin et al. 1999). An ocular survey provided 

evidence of its spread: in 2004, B. tectorum was present < 10 m from 15 plots, 

present < 2 m from 13 plots, and inside 4 plots. In 2005, B. tectorum was identified 

inside 7 plots and in 2006, inside 13 plots. This study was not designed to examine 

Figure 6—Relation of the mean cover of invasive, nonnative grasses to the mean 

cover of native grasses and forbs in the second year of growth. Seeds were sown in 

late September 2004 in twenty 1-m2

 plots at the Green Ridge site in the east-side 

central Oregon Cascade Range. 
26

GENERAL TECHNICAL REPORT PNW-GTR-823

competition effects. However, it appeared that survival and growth of sown species 

were not measurably affected when the density or cover of the nonnative grasses 

was low. This may be because invaders at first fill empty microsites (Tilman 1997). 

But if nonnative grasses reach a critical density or cover, the ability to establish 

native species from seed may be reduced (Beyers 2004, Forcella and Harvey 1983, 

Goodwin et al. 1999, Roundy et al. 2007). 

Summary and Conclusions

Most of the sown species emerged early and established to some degree on most of 

the plots. Frost heaving in early spring, high soil surface temperatures, insect predation, and the high density of invasive grasses appeared to be important microenvironmental factors that affected survival and growth rates. Some juvenile forb and 

most grass species increased vegetative cover through clonal spread, a secondary 

mechanism for their propagation and persistence (Liston et al. 2003). However, if 

invasive grasses became dense in the immediate vicinity of the emergent seeds, the 

rate of seedling growth and survival was reduced (Roundy et al. 2007, Young and 

Evans 1978). Most of the native species in this study are long-lived perennials that 

take several years to reach maturity and, thus, are vulnerable to extirpation before 

they reproduce. Sowing seeds in the fall capitalizes on the vernal growth habit of 

the native species and allows the seedlings’ maximum use of available moisture and 

nutrients for root and shoot growth. A secondary benefit might be increased competitiveness with annual nonnative grasses for limited resources (Beckstead

et al. 1995; Goodwin et al. 1995, 1996). 

Although traditional seed testing can yield information about a seed’s potential 

performance (USDA FS 2008), field seed germination tests based on accumulated 

emergence over the growing season can be used to build a database of information 

that would increase the predictability of survival and establishment of species under 

a range of conditions. Field tests have the added benefit of producing information 

on some of the key environmental and biological conditions that influence early 

survival and growth. The in situ seed germination evaluations increased our understanding of how environmental factors influence healthy germinating seed in the 

field. Unfortunately, because most of the species in this study did not reach maturity within the 2 years of observation, no inferences could be made about long-term 

establishment. To determine whether seeding can effectively introduce or accelerate 

the return of desired native species on degraded lands, monitoring for longer than 2 

to 3 years is essential. 

Dormancy may vary among seeds collected from a single location, which 

results in not all seeds germinating in the fall or spring (Goodwin et al. 1996, 
27

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Meyer and Kitchen 1994) and suggests an adaptation of these species to the highly 

variable temperature and moisture patterns on the east-side central Oregon Cascade 

Range. The evidence that seeds from a single source and species germinated at 

various times suggests that conditional dormancy and germination phenology of the 

grasses, the forb Linum lewisii, and possibly other species such as Penstemon humilis from this zone vary and should be examined further (Baskin and Baskin 1988, 

Meyer and Kitchen 1994, Meyer et al.1995). In addition to recognizing that there is 

variability within populations of critical seed traits such as dormancy and germination vigor, knowing the range in expression of those traits across the landscape will 

improve operational sowing strategies for seeds used in restoration or rehabilitation 

(Baskin and Baskin 1988, Meyer et al. 1995). 

Flowering herbs endemic to the dry transition forests of the east-side Cascades 

have a long evolutionary history of adaptation and fitness in ecosystems noted for 

disturbance. Not only an attractive part of the landscape, they contribute to nutrient cycling, energy flow, wildlife nutrition, and the support of diverse, beneficial 

insects (Brown and Amacher 1999). Biodiversity is usually assessed in the context 

of genetic variation, species diversity, and ecosystem complexity that occurs in 

a unit of space (Brown 2000, Erickson et al. 2004). However, the functionally 

diverse flora of a plant community suggests differences in how space is occupied, 

a key consideration when rehabilitating a landscape (Pillar 1999, Tilman 1997). 

For example, the diversity of the 18 vernal species used in this study includes the 

differences in functional traits and characteristics of monocots and dicots as well 

as differences among species in seed-germination phenology, seedling maturation and growth, growth form, and root and leaf morphology (Baskin and Baskin 

1988). Within the larger climatic and topographic sphere of influences, each species 

has evolved adaptive traits to function best (e.g., use limited resources) in its own 

microenvironment so that through natural selection and stochastic processes, the 

plant community may evolve toward optimal use of space and time (Pillar 1999, 

Tilman 1994). In the context of landscape rehabilitation or enhancement, the range 

of adaptability of any one species is not as effective in the long term as the aggregate range of adaptability of all its community members. However, the invasion of 

species following major or chronic disturbances disrupts the microniche function 

of the endemic species, particularly in semiarid systems. Invasions, unfortunately, 

are becoming more widespread, which increases the challenge of reestablishing 

the functionality of the native herbaceous flora while attempting to rehabilitate 

degraded landscapes (Chambers et al. 2007, Merriam et al. 2006, Monsen and 

Stevens 2004, Whisenant 1999). 

For each of the 18 species, information based on this study, published literature, 

and other documents may be found in appendix 2.
28

GENERAL TECHNICAL REPORT PNW-GTR-823

Glossary

achene—A dry indehiscent, one-seeded fruit, formed from a single carpel and with 

the seed distinct from the fruit wall.

anthesis—The duration of life of a flower from bud opening, to fruit set.

apomictic/apogamy—Production of viable seed without sexual union (double 

fertilization). 

awn—A long, bristle or thread-like outgrowth on glumes or lemmas found on tall 

grass species.

bolting—Rapid plant growth that goes from producing mostly leaves to producing 

mostly flowers and seeds.

caespitose—In tufts.

calyx—The whorl of sepals that collectively form the outer layer of the flower.

campanulate—Bell-shaped.

capitulum—The composite flower or seed head of members of the Asteraceae 

family.

carpel—The fertile female organ comprising the floral whorl known as the gynoecium of an angiosperm. Carpels may occur separately within the whorl or fuse 

together forming a compound structure (the pistil). 

caryopsis—Fruit of grasses in which the coat (testa) of the single seed is indistinct 

from the interconnective fruit wall.

caudex—A trunk or stock

coleoptile—A leafy sheath that covers the emergent shoot of a germinating grass 

seed in the family Poaceae.

colluvium—The soil accumulated at the foot of slopes. 

cordate—Heart shaped.

corolla—A collective term for the whorl, or whorls of petals in a flower.

cotyledon—An embryonic leaf formed from the embryo of an angiosperm or 

gymnosperm, and usually the first to appear upon germination. Monocotyledons 

typically have a single cotyledon; dicotyledons, two; and gymnosperms, several. 

culm—The jointed and usually flowering secondary stem of a grass or sedge.

cymose—Having an inflorescence that is headed by a terminal flower bud followed 

by lateral flowers.
29

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

dehisce—Open spontaneously along proscribed sutures to release pollen, spores, or 

seeds.

depauperate—Lacking species abundance normally found elsewhere.

epigeal—When seeds germinate, the cotyledons appear above ground.

filiform—Like a thread.

follicle—A many-seeded dry fruit derived from a single carpel that splits longitudinally down one side at dehiscence.

glabrous—Hairless. 

glume—Dry bract enclosing a grass spikelet.

hypogeal—When seeds germinate, the cotyledons remain below ground while the 

epicotyls elongate.

hypogynous ovary—Petals and sepals of flower attached at base of carpel or ovary.

in vitro—Outside a natural environment, usually in a laboratory.

inflorescence—The arrangement of flowers on a flowering stalk such as a raceme, 

spike, or cyme, without interruption by true, foliage leaves.

infructescence—Fruits formed of flowers making up an inflorescence.

involucre—A ring or cup of bracts (leaflike structures) that surround flowers under 

the capitulum (Asteraceae) or an umbel (Apiaceae).

lemma—Outer bract of a grass floret.

ligule—Membrane at junction of leaf base of grasses.

nectary—Modified plant tissue that secretes nectar.

outcross—The union of genes (cross fertilization) from one genetically distinct 

member of a species with another genetically distinct member.

papillate—Having papillae (small hair-like protuberances).

pappus—A ring of feathery hairs around fruit that act like a parachute; common in 

the Asteraceae family.

pedicel—The stalk of a flower in an inflorescence.

perianth—The floral envelope, calyx (sepals) or corolla (petals), or both. 

pericarp—Part of fruit enclosing seeds.

pls—Pure live seed.

pollinator limited—Reduced fruit or seed set in a population or species owing to 

inadequate visitation by known pollen vectors (pollinators). 

polyploidy—Having more than the usual two sets of chromosomes.

pubescence—Fuzz-like fine hairs on plant structures such as stems.
30

GENERAL TECHNICAL REPORT PNW-GTR-823

raceme—Inflorescence in which main axis bears flowers that bloom in succession 

toward the terminal.

rachis—Axis of pinnately compound leaf to which leaves are attached.

rhizome—A root-like stem lying horizontally on or under ground producing the 

buds of aerial (secondary) stems and bearing adventitious roots. 

rhizomatous—Having rhizomes. 

ruderal—Plant that readily grows in disturbed sites (waste places).

rugose—Wrinkled.

scabrous—Warty or with bumps.

scarification—Abrasion or other treatment to soften a hard seed coat of a dormant 

seed.

senescent—State of decline, dying.

sessile—Attachment on an organ to a stem without a connecting stalk. A sessile 

leaf lacks a petiole and a sessile flower lacks a pedicel.

spikelet—In grasses, a unit of the inflorescence in which a known cluster of flowers are subtended by the same pair of glumes.

staminode—Highly modified stamen.

stratification—Removal of seed dormancy through moisture and period of time in 

cold temperature.

tepals—Perianth organs in which true sepals or petals are anatomically 

indistinguishable. 

ternate—Compound leaf having three leaflets.

tiller—In grasses, a new shoot arising upward from an adventitious bud at or near 

the base of the original shoot. 

umbel—Inflorescence composed of flowers on stalks arising at same point resembling a flower head.

Sources: Hickey and King 2000, Porter 2008, Usher 1966.
31

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Acknowledgments

Many thanks go to Andrew Neill for his fine technical support and careful management of seeds, field and lab crews, and data and to Dan Mikowski for his expertise 

and time in laying out the study in the field. I also appreciate all the technical help 

and labor that was contributed to this study, especially by Lynn Larson, Emmalie 

Goodwin, and Zak Weinstein. Al Chase, volunteer, provided important help in the 

field in locating species in sufficient abundance for seed collecting. Thanks also 

to the staff at Lucky Peak Nursery for carrying out the growout study and collecting the data. I also thank Nancy Leeper for her editing expertise, Peter Bernhardt 

for lending his botanical expertise, and Bill Stein for his careful, thoughtful, and 

thorough review. The study was funded in part by the Native Plant Program NFN3 

from the USDA Forest Service. 

English Equivalents

When you know:	 Multiply by:	 To find:

Millimeters (mm) 0.0394 Inches (in)

Centimeters (cm) 0.394 Inches

Meters (m) 3.281 Feet (ft)

Meters 1.094 Yards (yd)

Kilometers .621 Miles

Square meters (m2

) 1.196 Square yards (yd2)

Square kilometers .386 Square miles

Hectares (ha) 2.471 Acres (ac)

Grams (g) 0.0022 Pounds (lb)

Kilograms (kg) 0.205 Pounds

Kilograms per hectare (kg/ha) 0.893 Pounds per acre (lb/ac)

Liters (L) 1.057 Quarts

Celsius (°C) 1.8 (+ 32) Fahrenheit (°F)

Pure live seeds per square meter .093 Pure live seeds per square

foot (pls/ft2)
32

GENERAL TECHNICAL REPORT PNW-GTR-823

Literature Cited

Agee, J.K. 1994. Fire and weather disturbances in terrestrial ecosystems of 

the eastern Cascades. Gen. Tech. Rep. PNW-GTR-320. Portland, OR: U.S. 

Department of Agriculture, Forest Service Pacific Northwest Research Station. 

52 p.

Apfelbaum, S.I.; Bader, B.J.; Faessler, F.; Mahler, D. 1997. Obtaining and 

processing seeds. In: Packard, S.; Mutel, C.F., eds. The tallgrass restoration 

handbook for prairies, savannas, and woodlands. Washington, DC: Island Press: 

99–126. Chapter 7.

Archer, A.J. 2000. Achnatherum thurberianum. In: Fire effects information 

system. Missoula, MT: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station, Fire Sciences Laboratory. http://www.fs.fed.us/

database/feis/. (October 4, 2006). 

Archibald, C. 2006. Seed production protocols for Anaphalis margaritacea, 

Eriophyllum lanatum and Eriogonum umbellatum. Native Plants. (7) 1: 47–51.

Arno, S.F. 2000. Fire in western forest ecosystems. In: Brown, J.K.; Smith, J.K., 

eds. Wildland fire in ecosystems effects of fire on flora. Gen. Tech. Rep. RMRSGTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, 

Rocky Mountain Research Station: 97–120.

Association of Official Seed Analysts [AOSA]. 2003a. Handbook on seeds of 

browse-shrubs and forbs. Atlanta, GA: Browse-Shrub and Forb Committee, 

Association of Official Seed Analysts and U.S. Department of Agriculture, 

Forest Service, Southern Region. 246 p. http://www.nsl.fs.fed.us/Handbook%20

on%20Seeds%20of%20Browse-Shrubs%20and%20Forbs.pdf. (December 2008).

Association of Official Seed Analysts [AOSA]. 2003b. Rules for testing seeds. 

Annapolis, MD: Rules committee of the Association of Official Seed Analysts. 

166 p.

Barbour, J. 2002. Uses of the Westrup brush machine. In: Dumroese, R.K.; 

Riley, L.E.; Landis, T.D., technical coordinators. National proceedings: forest 

and conservation nursery associations—1999, 2000, and 2001. Proceedings 

RMRS-P-24. Ogden, UT: U.S. Department of Agriculture Forest Service, Rocky 

Mountain Research Station: 245–249.

Baskin, C.C.; Baskin, J.M. 1988. Germination ecophysiology of herbaceous plant 

species in a termperate region. American Journal of Botany. 75(2): 286–305.
33

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Beckstead, J.; Meyer, S.E.; Allen, P.S. 1995. Effects of afterripening on 

cheatgrass (Bromus tectorum) and squirreltail (Elymus elymoides) germination. 

In: Roundy, B.A.; McArthur, E.D.; Haley, J.S.; Mard, D.K., eds. Proceedings: 

wildland shrub and arid land restoration symposium. Gen. Tech. Rep. INTGTR-315. Ogden, UT: U.S. Department of Agriculture, Forest Service, 

Intermountain Research Station: 165–172.

Beyers, J.L. 2004. Postfire seeding for erosion control: effectiveness and impacts 

on native plant communities. Conservation Biology. 18(4): 947–956.

Brown, C.S.; Rice, K.J. 2000. The mark of Zorro: effects of the exotic annual 

grass Vulpia myuros on California native perennial grasses. Restoration Ecology. 

8(1): 10–17.

Brown, J.K. 2000. Ecological principles, shifting fire regimes and management 

considerations. In: Brown, J.K.; Smith, J.K., eds. Wildland fire in ecosystems 

effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station: 

185–203. 

Brown, R.W.; Amacher, M.C. 1999. Selecting plant species for ecological 

restoration: a perspective for land managers. Revegetation with native 

species, proceedings 1997 Society for Ecological Restoration annual meeting. 

RMRS-P-8. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station: 1–16.

Burgett, D.M.; Stringer, B.A.; Johnston, L.D. 1989. Nectar and pollen plants of 

Oregon and the Pacific Northwest. Blodgett, OR: Honeystone Press. 151 p. 

Burton, P.J.; Burton, C.M. 2002. Promoting genetic diversity in the production of 

large quantities of native plant seed. Ecological Restoration 20. (2): 117–123.

Cane, J. 2005. Pollination needs of arrowleaf balsamroot, Balsamorhiza sagittata

(Heliantheae: Ateraceae). Western North American Naturalist. 65(3): 359–364.

Cane, J.; Weber, M.; Yost, M.; Gardner, D. 2004. Alkaloids and old lace:

pollen toxins exclude generalist pollinators from death camas (Toxicoscordion

[= Zigadenus] paniculatum) (Melanthiaceae). [Abstract]. Salt Lake City, UT.

http://www.2004.botanyconference.org/engine/search/index.

php?func=detail&aid=1128. (January 2009).

Cavers, P.B.; Steel, M.G. 1984. Patterns of change in seed weight over time on 

individual plants. American Naturalist. 124: 324–335.
34

GENERAL TECHNICAL REPORT PNW-GTR-823

Cavieres, L.A.; Arroyo, M.T.K. 2000. Seed germination response to cold 

stratification period and thermal regime in Phacelia secunda (Hydrophyllaceae). 

Plant Ecology. 149: 1–8.

Chambers, J.C.; Roundy, B.A.; Blank, R.R.; Meyer, S.E.; Whittaker, A. 2007.

What makes Great Basin sagebrush ecosystems invasible by Bromus tectorum? 

Ecological Monographs. 77(1): 117–145.

Clinebell, R.R.; Bernhardt, P. 1998. The pollination ecology of five species of 

Penstemon (Scrophulariaceae) in the tallgrass prairie. Annals of the Missouri 

Botanical Garden. 85: 126–136.

Close, D.C.; Beadle, C.L.; Battaglia, M. 2004. Foliar anthocyanin accumulation 

may be a useful indicator of hardiness in eucalypt seedlings. Forest Ecology and 

Management. 198: 169–181.

Daehler, C.C. 2003. Performance comparisons of co-occurring native and alien 

invasive plants: implications for conservation and restoration. Annual Revue of 

Ecological Systematics. 34: 183–211. 

Darris, D. 2007. Fact sheet pine bluegrass Poa secunda J. Presl. Corvallis, OR: 

U.S. Department Agriculture, Natural Resources and Conservation Service, 

Plant Materials Center. http://Plant-Materials.nrcs.usda.gov. (February 17, 2009).

Deering, R.H.; Young, T.P. 2006. Germination speeds of exotic annual and 

native perennial grasses in California and the potential benefits of seed 

priming for grassland restoration. Grasslands. 16(1): 13–17. http://ucdavis.edu/

publications/2006Priming.pdf. (March 2009).

Doescher, P.; Miller, R.; Winward, A. 1985. Effects of moisture and temperature 

on germination of Idaho fescue. Journal of Range Management. 38: 317–320.

Douglas, J.; Grabowski J.; Keith, B. 1997. A comparison of seed cleaning 

techniques for improving quality of eastern gamagrass seed. Jackson, MS: U.S. 

Department of Agriculture, Natural Resource Conservation Service. Technical 

Note. 13(7): 43–47.

Drake, D.; Ewing, K.; Dunn, P. 1998. Germination of native plant seeds from the 

south Puget Sound prairies of Washington state. Restoration and Management 

Notes. 16(1): 33–40.

Durham, R.E.; Sackschewsky, M.R. 2004. W-519 Sagebrush mitigation project 

FY-2004 final review and status. Richland, WA: U.S. Department of Energy, 

Pacific Northwest National Laboratory. 88 p.
35

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Ellison, R.L.; Thompson, J.N. 1987. Variation in seed and seedling size: the 

effects of seed herbivores on Lomatium grayi (Umbelliferae). Oikos 49: 269–280.

Erickson, V.J.; Mandel, N.L.; Sorensen, F.C. 2004. Landscape patterns of 

phenotypic variation and population structuring in a selfing grass, Elymus 

glaucus (blue wildrye). Canadian Journal of Botany. 82: 1776–1789.

Evans, R.A.; Young, J.A. 1978. Effectiveness of rehabilitation practices following 

wildfire in a degraded big sagebrush-downy brome community. Journal of Range 

Management. 31(3): 185–188. 

Flessner, T.R.; Darris, D.C. 2001. Progress report of activities year 2000. 

Corvallis, OR: USDA Natural Resources Conservation Service Plant

Materials Center. http://plant-materials.nrcs.usda.gov/pubs/orpmcra2000.pdf. 

(December 2008).

Forcella, F.; Harvey, S.J. 1983. Eurasian weed infestation in western Montana in 

relation to vegetation and disturbance. Madrono. 30: 102–109. 

Franklin, J.F.; Dyrness, C.T. 1973. Natural vegetation of Oregon and Washington. 

Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Forest and Range Experiment Station. 417 p.

Gardenbed 2004. http://www.gardenbed.com. (August 15, 2006).

Gilky, H.M.; Dennis, L.R.J. 2001. Handbook of Northwestern plants. Corvallis, 

OR: Oregon State University Press. 494 p. 

Goldblatt, P.; Manning, J.C. 2009. The iris family natural history and classification. Portland, OR: Timber Press, Inc. 336 p.

Goodwin, J.R.; Doescher, P.S.; Eddleman, L.E. 1995. After-ripening in 

Festuca idahoensis seeds: adaptive dormancy and implications for restoration. 

Restoration Ecology. 3(2): 137–142.

Goodwin, J.R.; Doescher, P.S.; Eddleman, L.E. 1996. Germination of Idaho 

fescue and cheatgrass seeds from coexisting populations. Northwest Science. 

70(3): 230–241.

Goodwin, J.R.; Doescher, P.S.; Eddleman, L.E; Zobel, D.B. 1999. Persistence of 

Idaho fescue on degraded sagebrush steppe. Journal of Range Management. 52: 

187–198.

Groen, A.H. 2005. Apocynum androsaemifolium. In: Fire Effects Information 

System. U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station, Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. 

(May 09, 2006). 
36

GENERAL TECHNICAL REPORT PNW-GTR-823

Gundale, M.J.; Sutherland, S.; DeLuca, T.H. 2008. Fire, native species, and soil 

resource interactions influence the spatio-temporal invasion pattern of Bromus 

tectorum. Ecography. 31: 201–210. 

Hardegree, S.P.; Jones, T.A.; VanVactor, S.S. 2002. Variability in thermal 

response of primed and non-primed seeds of squirreltail (Elymus elymoides

(Raf.) Swezey and Elymus multisetus (J.G. Smith) M.E. Jones). Annals of Botany. 

89: 311–319.

Harmond, J.E.; Brandenburg, N.R.; Klein, L.M. 1968. Mechanical seed 

cleaning and handling. U.S. Department of Agriculture. Agric. Handb. 354. 

Washington, D.C. 54 p.

Hassell, W.; Beavers, W.R.; Ouellette, S.; Mitchell, T., comps. 1996. Seeding 

rate statistics for native and introduced species [tables]. Washington, DC: 

U.S. Department of the Interior, National Park Service; U.S. Department of 

Agriculture, Natural Resources Conservation Service. 26 p. 

Hickey, M.; King, C. 2000. The Cambridge illustrated glossary of botanical terms. 

Cambridge, New York: Cambridge University Press. 208 p.

Hitchcock, A.S. 1951. Manual of the grasses of the United States. 2nd ed. revised. 

New York: Dover Publishing, Inc. 569 p. Vol. 1.

Hitchcock, C.L; Cronquist, A. 1973. Flora of the Pacific Northwest. Seattle, WA: 

University of Washington Press. 730 p. 

Howard, J.L. 1992. Zigadenus venenosus. In: Fire Effects Information System. 

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research 

Station, Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/.

(October 4, 2006).

Howard, J.L. 1997. Poa secunda. In: Fire Effects Information System. U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, 

Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. (October 4, 2006).

Howard, J.L. 2006. Vulpia myuros. In: Fire Effects Information System.

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research 

Station, Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/.

(December 4, 2008).

Iriondo, J.M.; Perez, C. 1999. Propagation from seeds and seed preservation. In: 

Bowes, B.G., ed. Plant propagation and conservation. New York: The New York 

Botanical Garden Press: 46–57.
37

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Johnson, C.G. 1998. Vegetation response after wildfires in national forests of 

northeastern Oregon. R6-NR-ECOL-TP-06-98. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Region. 128 p. + appendices.

Johnson, S.A.; Bruederle, L.P.; Tomback, D.F. 1998. A mating system 

conundrum: hybridization in Apocynum (Apocynaceae). American Journal

of Botany. 85(9): 1316–1323. 

Jones, T.A. 2006. Plant guide. Bottlebrush squirreltail and big squirreltail (Elymus

elymoides (Raf.) Swezey and Elymus multisetus M.E. Jones). http://plants.usda.

gov/plantguide/pdf/pg_elmu3.pdf. (July 2010).

Jorgensen, K.R.; Wilson, G.R. 2004. Seed germination. In: Monsen, S.B.; 

Stevens, R.; Shaw, N.L., comps. Restoring western ranges and wildlands.

Gen. Tech. Rep. RMRS-GTR-136-vol-3. Fort Collins, CO: U.S. Department

of Agriculture, Forest Service, Rocky Mountain Research Station: 723–732. 

Kearns, C.A.; Inouye, D.W. 1994. Fly pollination of Linum lewisii (linaceae). 

American Journal of Botany. 81(9): 1091–1095.

Keeley, J.E. 2004. Ecological impacts of wheat seeding after a Sierra Nevada 

wildfire. International Journal of Wildland Fire. 13: 73–78.

Kephart, S.; Reynolds, R.J.; Rutter, M.T.; Fenster, C.B.; Dudash, M.R. 2006.

Pollination and seed predation by moths on Silene and allied Caryophyllaceae: 

evaluating a model system to study the evolution of mutualisms. New 

Phytologist. 169: 667–680.

Kruckeberg, A.R. 1982. Gardening with native plants of the Pacific Northwest: an 

illustrated guide. Seattle, WA: University of Washington Press. 252 p. 

Kruskal, W.H.; Wallis, W.A. 1952. Use of ranks in one-criterion variance 

analysis. Journal of the American Statistical Association. 47(260): 583–621.

Lambert, S. 2005. Guidebook to the seeds of native and non-native grasses, forbs 

and shrubs of the Great Basin. Tech. Bull. 2005-04. Boise, ID: U.S. Department 

of the Interior, Bureau of Land Management. 133 p. 

Legler, B., contributor. 2006. Burke Museum of Natural History and Culture 

[Database]. Seattle, WA: University of Washington. http://biology.burke.

washington.edu/herbarium/imagecollection.php?Genus=Olsynium&Species=

douglasii. (December 2008).
38

GENERAL TECHNICAL REPORT PNW-GTR-823

Linhart, Y.B. 1995. Restoration, revegetation, and the importance of genetic and 

evolutionary perspectives. In: Roundy, B.A.; McArthur, E.D.; Haley, J.S.; Mard, 

D.K., eds. Proceedings: wildland shrub and arid land restoration symposium. 

Gen. Tech. Rep. INT-GTR-315. Ogden, UT: U.S. Department of Agriculture, 

Forest Service, Intermountain Research Station: 271–287.

Liston, A.; Wilson, B.L.; Robinson, W.A.; Doescher, P.S.; Harris, N.R.; 

Svejcar, T. 2003. The relative importance of sexual reproduction versus clonal 

spread in an aridland bunchgrass. Oecologia. 137: 216–225.

Lodewick, R.; Lodewick, K. 1999. Key to the genus Penstemon. Eugene, OR:

10th Ave. Press. 136 p. 

Lofflin, D.L.; Kephart, S.R. 2005. Outbreeding, seedling establishment, and 

maladaptation in natural and reintroduced populations of rare and common 

Silene douglasii (Caryophyllaceae). American Journal of Botany. 92(10): 

1691–1700. 

Martens, E.; Palmquist, D.; Young, J.A. 1994. Temperature profiles for 

germination of cheatgrass versus native perennial bunchgrasses. In: Monsen, 

S.B.; Kitchen, S.G., comps. Proceedings―ecology and management of annual 

rangelands. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of 

Agriculture, Forest Service, Intermountain Research Station: 238–243. 

McKown, R.; Kuroki, G.; Warren, G. 1996. Cold responses of Arabidopsis

mutants impaired in freezing tolerance. Journal of Experimental Botany. 47: 

1919–1925.

McWilliams, J. 2002. Balsamorhiza sagittata. In: Fire Effects Information

System. U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station, Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. 

(October 4, 2006).

Merriam, K.E.; Keeley, J.E.; Beyers, J.L. 2006. Fuel breaks affect nonnative 

species abundance in Californian plant communities. Ecological Applications. 

16(2): 515–527.

Meyer, S.E.; Kitchen, S.G. 1994. Life history variation in blue flax (Linum 

perenne: Linaceae): seed germination phenology. American Journal of Botany. 

81(5): 528–535.

Meyer, S.E.; Kitchen, S.G.; Carlson, S.L. 1995. Seed germination timing patterns 

in intermountain Penstemon (Scrophulariaceae). American Journal of Botany. 

82: 377–389.
39

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Miller, H.C.; Clausnitzer, D.; Borman, M.M. 1999. Medusahead. In: Sheley, 

R.L.; Petroff, J.K., eds. Biology and management of noxious rangeland weeds. 

Corvallis, OR: Oregon State University Press. 438 p.

Miller, M.T.; Antos, J.A.; Allen, G.A. 2004. Dormancy and flowering in two 

mariposa lilies (Calochortus) with contrasting distribution patterns. Canadian 

Journal of Botany. 82: 1790–1799

Monsen, S.B.; Stevens, R. 2004. Seedbed preparation and seeding practices. 

In: Monsen, S.B.; Stevens, R.; Shaw, N.L., comps. Restoring western ranges 

and wildlands. Gen. Tech. Rep. RMRS-GTR-136-Vol 1. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station: 

121–154. 

Mosely, J.C.; Bunting, S.C.; Monoukian, M.E. 1999. Cheatgrass. In: Sheley, 

R.L.; Petroff, J.K., eds. Biology and management of noxious rangeland weeds. 

Corvallis, OR: Oregon State University Press: 175–188. 

O’Brien, M.H. 1980. The pollination biology of a pavement plain: pollinator 

visitation patterns. Oecologia. 47: 213–218. 

Ogle, D.G. 2008. Plant Guide Pseudoroegnaria spicata. Boise, ID: U.S. Department of Agriculture, Natural Resources Conservation Service, Idaho State 

Office. http://Plant-Materials.nrce.usda.gov. (February 18, 2009).

Ollerton, J.; Lack, A. 1996. Partial predispersal seed predation in Lotus 

corniculatus L. (Fababceae) Seed Science Research. 6: 65–69.

Oregon Climate Service. 2009. Online climate data. Corvallis, OR: Oregon State 

University. http://www.ocs.oregonstate.edu. (February 16, 2009).

Parkinson, H., comp. 2003. Landscaping with native plants of the Intermountain 

Region. Tech. Ref. 1730-3. Boise, ID: U.S. Department of the Interior, Bureau of 

Land Management, Idaho State Office. 47 p.

Parkinson, H.; DeBolt, A. 2005a. Propagation protocol for production of container 

Eriogonum umbellatum Torr. plants. In: Native Plant Network. Moscow, ID: 

University of Idaho, College of Natural Resources, Forest Research Nursery. 

http://www.nativeplantnetwork.org. (February 17, 2009).

Parkinson, H.; DeBolt, A. 2005b. Propagation protocol for production of container 

Lomatium triternatum (Pursh.) Coult. & Rose. plants. In: Native Plant Network. 

Moscow, ID: University of Idaho, College of Natural Resources, Forest Research 

Nursery. http://www.nativeplantnetwork.org. (February 17, 2009).
40

GENERAL TECHNICAL REPORT PNW-GTR-823

Pendleton, R.L.; Kitchen, S.G.; Mudge, J.; McArthur, E.D. 2008. Origin of 

the flax cultivar “Appar” and its position within the Linum perenne complex. 

International Journal of Plant Sciences. 169(3): 445–453.

Peters, J., ed. 2000. Tetrazolium testing handbook. Contribution No. 29 to the 

Handbook on seed testing. Lincoln, NE: Association of Official Seed Analysts.

Pettersson, M.W. 1991. Flower herbivory and seed predation in Silene vulgaris 

(Caryophyllaceae): effects of pollination and phenology. Ecography. 14(1): 45–50.

Pillar, V.D. 1999. On the identification of optimal plant functional types. Journal of 

Vegetation Science. 10: 631–640.

Pojar, J.; Mackinnon, A., comps. 1994. Plants of the Pacific Northwest coast. 

Edmonton, AB: Lone Pine Publishing. 528 p.

Porter, C.L. 2008. Taxonomy of flowering plants. Caldwell NJ: The Blackburn 

Press. 488 p.

Reeves, S.L. 2006. Linum lewisii. In: Fire Effects Information System. U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, 

Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. (March 21, 2007).

Robichaud, P.R.; Beyers, J.L.; Neary, D.G. 2000. Evaluating the effectiveness of 

postfire rehabilitation treatments. Gen. Tech. Rep. RMRS-GTR-63. Fort Collins, 

CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research 

Station. 85 p. 

Rose, R.; Chachulski, C.E.C; Haase, D.L. 1998. Propagation of Pacific Northwest 

native plants. Corvallis, OR: Oregon State University Press. 248 p.

Roundy, B.A.; Hardegree, S.P.; Chambers, J.C.; Whittaker, A. 2007. Prediction 

of cheatgrass field germination potential using wet thermal accumulation. 

Rangeland Ecology and Management. 60: 613–623.

Schoennagel, T.L.; Waller, D.M. 1999. Understory responses to fire and artificial 

seeding in an eastern Cascades Abies grandis forest, U.S.A. Canadian Journal of 

Forest Research. 29: 1393–1401.

Sheley, R.L.; Half, M.L. 2006. Enhancing native forb establishment and 

persistence using a rich seed mixture. Restoration Ecology. 14(4): 627–635.

Simonin, K.A. 2001. Elymus elymoides. In: Fire Effects Information System, U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, 

Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. (October 4, 2006). 
41

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Simpson, M. 2007. Forested plant associations of the Oregon East Cascades. Tech. 

Pap. R6-NR-ECOL-TP-03-2007. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Region. http://www.reo.gov/ecoshare/

Publications/documents/080702FS-MS_Forested_Plant_Assn_lores.pdf.

(April 21, 2009).

Suna, H.; Van Campen, B. 2003. Eyerly Fire weed BAER monitoring report 

Sisters Ranger District. 6 p. Unpublished report. On file with: USDA Forest 

Service, Deschutes National Forest, Sisters Ranger District, P.O. Box 249, 

Sisters, OR 97759.

Tepedino, V.J. 2003. What’s in a name? The confusing case of the death camas 

bee, Andrena astragali Viereck and Cockerell (Hymenoptera: Andrenidae). 

Journal of Kansas Entomological Society. 76(2): 194–197. 

Thompson, J.N.; Pellmyr, O. 1989. Origins of variance in seed number and 

mass: interaction of sex expression and herbivory in Lomatium salmoniflorum. 

Oecologia. 79: 395–402.

Tilman, D. 1994. Competition and biodiversity in spatially structured habitats. 

Ecology. 75(1) 2–16.

Tilman, D. 1997. Community invasibility, recruitment limitation, and grassland 

biodiversity. Ecology. 78(1): 81–92.

Tyson, H. 1989. Genetic control of seed weight in flax (Linum usitatissimum) and 

possible implications. Theoretical and Applied Genetics. 77: 260–270.

U.S. Department of Agriculture, Forest Service [USDA FS]. 1937 [reprinted

1988]. Range plant handbook. Mineola, NY: Dover Publications. 816 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2002. Eyerly 

Fire Burned-Area Report. Bend, OR: Deschutes and Ochoco National Forests, 

Crooked River National Grassland, Fire & Aviation. http://www.fs.fed.us/r6/

centraloregon/fires/2002/eyerly/baer.shtml. (December 2006).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2004a. Burnedarea emergency rehabilitation. FSM 2500, Ch. 2523. Amend. 2500–2004-1. 

Washington, DC.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2004b. Final 

environmental impact statement Eyerly Fire Salvage Project. Sisters, OR: Sisters 

Ranger District, Deschutes National Forest. 604 p.
42

GENERAL TECHNICAL REPORT PNW-GTR-823

U.S. Department of Agriculture, Forest Service [USDA FS]. 2006a. Notice 

of Proposed Native Plant Material Policy, Forest Service Manual (FSM) 2070. 

Native Plants. Federal Register. 71(102): 30375-30376. http://www.nplnews.com/

fedregister/2006/may262006-fs-plant-fsm2070.htm. (December 2008). 

U.S. Department of Agriculture, Forest Service [USDA FS]. 2006b. Bend, OR: 

Bend Seed Extractory. http://www.nps.gov/plants/sos/bendcollections/index.htm. 

(January 2007). 

U.S. Department of Agriculture, Forest Service [USDA FS]. 2008. Nursery 

manual for native plants: a guide for tribal nurseries. Vol 1. Nursery 

Management. Dumroese, R.K.; Luna, T.; Landis, T.D., eds. Agriculture 

Handbook 730. 

U.S. Department of Agriculture, Natural Resources Conservation Service 

[USDA NRCS]. 2006. The PLANTS Database, version 3.5. Baton Rouge, LA: 

National Plant Data Center. http://plants.usda.gov. (October 23, 2008).

U.S. Department of the Interior Bureau of Land Management [USDI BLM].

2003. Landscaping with native plants of the Intermountain Region. Tech. Ref. 

1730-3. Boise, ID. 47 p.

Usher, G. 1966. The Wordsworth dictionary of botany. London: Constable and

Co., Ltd. 404 p.

Valencia-Diaz, S.; Montaña, C. 2005. Temporal variability in the maternal 

environment and its effect on seed size and seed quality in Flourensia cernua

DC. (Asteraceae). Journal of Arid Environments. 63: 686–695.

Vance, N.; Neill, A.; Morton, F. 2006. Native grass seeding and forb planting 

establishment. Native Plants Journal. 7(1): 35–46.

Whisenant, S.G. 1999. Repairing damaged wildlands a process-oriented, 

landscape-scale approach. Cambridge, United Kingdom: Cambridge University 

Press. 312 p. 

Wickens, G.E. 1998. Ecophysiology of economic plants in arid and semi-arid 

lands. New York: Springer. 343 p.

Wilderman, D.L. 2003. Effects of wildfire on high-quality shrub-steppe vegetation, Cleveland Natural Area Preserve, south-central Washington state. The 

Phlox Phlyer—Newsletter of the Columbia Basin Chapter of the Washington 

Native Plant Society. 7(6): 1–2.
43

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Wright, J.W.; Meagher, T.R. 2003. Pollination and seed predation drive flowering 

phenology in Silene latifolia (Caryophyllaceae). Ecology. 84(8): 2062–2073.

Young, J.A.; Evans, R.A. 1978. Population dynamics after wildfires in sagebrush 

grasslands. Journal of Range Management. 31(4): 283–289. 

Young, J.A.; Evans, R.A. 1979. Arrowleaf balsamroot and mules ear seed 

germination. Journal of Range Management. 32(1): 71–74.

Young, J.A.; Young, C.G. 1986. Seeds of wildland plants. Portland, OR: Timber 

Press, Inc. 236 p.

Zlatnik, E. 1999. Pseudoroegneria spicata. In: Fire Effects Information

System. U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station, Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. 

(October 4, 2006).

Zouhar, K.L. 2000. Festuca idahoensis. In: Fire Effects Information System. U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, 

Fire Sciences Laboratory. http://www.fs.fed.us/database/feis/. (October 4, 2006).
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Appendix 1: Growout Results at Lucky Peak Nursery 

An important consideration when developing a seed collection program is to find 

local seed collection areas that will provide maximum number of viable seeds for 

the minimum expenditure of resources. Possible seed transfer issues can be circumvented by selecting areas as close as possible to the areas planned for treatment. 

However, this may present a constraint if these locations do not have enough plants 

to supply sufficient seed. When seed sources appear to be inadequate for supplying 

local seed, or seed collection in the wild becomes infeasible, nurseries that increase 

seed through cultivation may be used to supply seeds for rehabilitation and restoration (Archibald 2006). If seed transfer guidelines are not known, seeds for nursery 

production are often collected from parent plants distributed across an area thought 

to represent the range of conditions to which the species has adapted and where the 

seeds will be used. This strategy is used in part because small seed lots are costly 

and more difficult to manage. However, broad collections to bracket genetic adaptation in the long term may be costly as well if establishment rates are low (Burton 

and Burton 2002). 

To determine the feasibility of increasing seeds collected from a restricted 

seed collection area < 26 km2

 (10 mi2), seeds from native herbaceous species 

were collected at Green Ridge, on the Sisters Ranger District, Deschutes National 

Forest, during the summer of 2005. The cleaned seeds were brought to the Lucky 

Peak Nursery north of Boise, Idaho (Clarke Fleege, Nursery Manager, Lucky Peak 

Nursery, Boise National Forest). The seeds were sown in the fall of that year to test 

the efficacy of growing plants to maturity under nursery conditions to produce seed 

for future use by the district. Enough seeds of 11 species were available for sowing, 

including 4 grass and 7 forb species (table 6). 

Of the 11 species grown from seed, only Lomatium triternatum and Balsamorhiza careyana did not reach maturity, flower, and produce seeds (table 6). These 

two, deep-rooted and long-lived species take several years to mature in the wild. 

The other species produced seeds that were collected once or twice over 3 years. 

The percentage of the yield in some cases exceeded 10,000 percent (table 6). Silene 

douglasii was notable for its high productivity in the nursery setting: from 0.08 lb 

of seed sown in 2005, the accumulated amount of seed produced from 2007 through 

2008 was about 14 lb. This high rate of yield suggests that S. douglasii would be 

an excellent candidate for nursery growout. Lotus crassifolius also benefited from 

nursery conditions: from about 0.5 lb of seed, this species was able to produce 15 lb 

in 2 of the 3 years. Most of the species required 2 years to reach sufficient maturity 
45

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Table 6—Seed yield by weight and percentage of the growout seed production at Lucky Peak Nursery Boise, 

Idaho, from seeds of native forb and grass seeds collected at Green Ridge on the Deschutes National Forest, 

east-side central Oregon Cascades Range

Harvest date Yield

Sown

Species	 seed 	 2007	 2008	 2006	 2007	 2008 	 Total	 Increase

Pounds – – – – – – – Pounds – – – – – – – Percent

Forbs:

Balsamorhiza careyana 0.25 N.H. N.H.

Eriogonum umbellatum 0.20 N.H. 7/30 25.00 5.48 30.48 15,140

Eriophyllum lanatum 0.10 7/18 N.H. 32.00 32.00 31,900

Linum lewisii var. lewisii 0.10 6/28 N.H. 0.05 0.50 0.55 450

Lomatium triternatum 0.30 N.H. N.H.

Lotus crassifolius 0.40 N.H. 7/24 15.45 15.45 3,762

Silene douglasii 0.08 7/12 7/15 13.51 0.45 13.96 17,350

Grasses:

Elemus elymoides 0.30 6/25 7/2 2.74 21.75 2.57 27.06 8,920

Festuca idahoensis 0.08 6/16 6/26 9.00 2.15 11.15 13,838

Poa secunda 0.05 6/20 7/2 8.50 4.46 12.96 25,820

Pseudoroegnaria spicata 0.25 6/20 7/2 3.50 0.81 4.31 1,624

N.H. = No harvest.

for seed production. The exceptions were Elymus elymoides and Linum lewisii,

which produced a low amount of seed the first year. 

The results of this growout trial demonstrate that nurseries can play an essential 

role for efficiently increasing the amount of seed of diverse species that would be 

needed for wide-scale seeding programs. Because 2 years is probably a minimum 

and may be optimum for most species to obtain high seed yield, postfire seeding 

would not be possible with this seed immediately after a burn. It is important that 

seed be collected and properly stored so it could become the basis of an ongoing 

seed bank program. Seeds of key native plant species collected from representative 

locations of a plant association and within an effective elevational range would then 

be made available in the event of fire or other disturbance that occurred in comparable locations. 
46

GENERAL TECHNICAL REPORT PNW-GTR-823
47

Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone

Appendix 2: Summarized Information by Species

All taxonomic nomenclature follows USDA NRCS PLANTS Database, National 

Plant Data Center, Baton Rouge, LA 70874-4490 USA.

(http://plants.usda.gov, 5 June 2009). 
48 GENERAL TECHNICAL REPORT PNW-GTR-823

Apocynum androsaemifolium L. 

Spreading dogbane 

Apocynaceae

APAN2

Apocynum androsaemifolium L. is a rhizomatous, perennial herb with 

branching, erect stems 20–50 cm having opposite, somewhat drooping, ovate 

leaves. Stems and leaves have a milky sap. The inflorescence is cymose with 

campanulate or tubular flowers; the corolla is white to pink with pink veins, 

5–10 mm; filaments of stamens curved so that anthers converge over stigma, 

pistil surrounded at base by five nectaries; fruit are long, narrow follicles 

that turn from green to pinkish brown when mature; tapering cylindrical 

seeds have attached, tufted hairs.

Distribution and habitat

Range is from Alaska and Canada south throughout most of the United 

States except for the Southeast. It has a broad distribution across a range of 

environments, plant community types, and elevations (50–2000 m) on dry 

hillsides, riparian zones, valleys, and foothills, to semialpine slopes. Grows 

in open woods, meadows, along woodland edges and roadsides, and in 

disturbed openings such as powerline rights-of-way; an early seral species 

but also tolerates shade. Apocynum androsaemifolium is fire adapted with 

deep rhizomes that regenerate after wildfire. 

Reproductive ecology

Apocynum androsaemifolium is self-incompatible, and therefore, relies on 

sexual reproduction through insect vectors to reproduce. However, it appears 

to persist primarily through rhizomatous propagules to the extent that a 

colony of A. androsaemifolium might be a clone. The species has a long 

flowering interval, which for the east-side central Oregon Cascade Range 

may be from June through August. Although the plant is reportedly toxic 

to livestock, the flowers produce nectar that attracts and helps to support 

a wide variety of insects important to the pollination of associated plants. 

Apocynum androsaemifolium also has been described as “keystone prey” for 

insects. About 71 species have been recorded visiting the flowers including 

bees, wasps, flies, butterflies, and moths. Although most insects appear to 

visit the flowers for nectar, few have been found carrying A. androsaemifolium pollen, and the effective pollinator has not been identified. The reported 

fruit-to-flower ratio is low, or < 2 percent and seed set is poor; however, the APAN2
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 49

filled-seed rate of seeds collected at Green Ridge in the east-side Oregon 

Cascade Range was 53.8 percent in 2004. Seeds have hairs and are wind 

dispersed. 

Propagation

Seeds mature from mid September through early October. Because this 

species is so clonal in its propagation, care should be taken to collect seeds 

from colonies that are distinctly separated from each other to ensure genetic 

diversity in the seed mix. Mature fruits are harvested by hand from mid 

through late September at Green Ridge. The long, narrow follicles are collected just before they split but when as dry as possible, placed in paper bags, 

and returned to the lab to dry further. After a few days to a week when they 

are dry and brittle and split easily, seeds are removed. Seeds are light brown 

when they are mature; dark brown seeds are usually empty. The tufted hairs 

detach readily from the seeds and tend to float in the air. Seeds can easily be 

cleaned with screens. Of fresh seeds from Green Ridge that dried 2 weeks 

in the lab, the number per kilogram was 2,684,700. The seeds store well, but 

seeds require cold stratification (1–4 o

C) before sowing. Viability can be 

low; seeds tetrazolium (TZ) tested from the Puget Sound lowland prairie had 

10-percent viability, and germination with 12 weeks stratification was 2 percent. Filled seed was 54 percent and seed viability of the Green Ridge seeds 

by tetrazolium testing was 55 percent. The germination rate on seeds stratified for 10 weeks was 28.0 percent with 74.8 percent of the seeds moldy. 

Low seed viability and poor germination may be due to self pollination or 

lack of maturity. The study seeds sown at Green Ridge in late September 

germinated poorly (< 2 percent). The trend in emergence and survival peaks 

in early May as shown in figure A1. There were virtually no survivors the 

following year. Apocynum androsaemifolium is reportedly difficult to grow 

in poor-quality soil, but grows well under greenhouse conditions and once 

established, under the right conditions, can become weedy. We observed 

plants resprouting from live root crowns or rhizomes below the soil surface 

2 years after a wildfire at Green Ridge. In areas where this species is part 

of the prefire community, propagation by planting rather than seeding may 

result in better establishment. 

References

Drake et al. (1998), Gardenbed (2004), Gilky and Dennis (2001), Groen 

(2005), Hitchcock and Cronquist (1973), Johnson et al. (1998), Pojar and 

Mackinnon (1994), USDA FS (1988), USDA NRCS (2006).

APAN2
50 GENERAL TECHNICAL REPORT PNW-GTR-823

Balsamorhiza careyana Gray

Carey’s balsamroot

Asteraceae

BACA3

Balsamorhiza careyana is a long-lived, cool-season, perennial herb with 

a deep-seated, woody taproot. Basal leaves originating from a caudex are 

triangular, large, and green on both surfaces, sparsely hairy, cordate at base, 

5–30 cm long and 5–10 cm wide. Multiple stems, each topped with one to 

multiple heads that radiate with a composite of disc and ray flowers having 

multiple overlapping bracts around base; fruit are achenes. Leaves of seedlings covered with fine hairs.

Distribution and habitat

Range is along the eastern Cascades from southern British Columbia to 

central Oregon. East of the Cascade Range, B. careyana can be found within 

the low and mid elevations from 300 to 1900 m, growing on open ridges, dry 

foothills, semiarid mountain rangelands, and on southerly exposures. Within 

its limited range, B. careyana occurs commonly in Pinus ponderosa/Purshia 

tridentata/Festuca idahoensis and dry Pseudotsuga menziesii, Quercus, and 

Artemesia associations in open sites that may become hot and dry. It grows 

on well-drained stony, silty, and loamy soils. Like B. sagittata, it is palatable 

to a wide range of wildlife. Prefers full sun but can grow in partial shade of 

canopy. 

Reproductive ecology

Balsamorhiza species may take several years of growth to produce a flower 

in its natural habitat. Balsamorhiza sagittata is reported to exhibit self 

compatibility, but viable seed benefits from out-crossed pollen. Flowering occurs from late March through July. The flowers produce nectar that 

attracts insects and may be, like the nectar of B. deltoidea, high in sugar 

concentration. Flowers attract a variety of insects including bees, flies, 

and butterflies. Effective pollinators are small, solitary bees that rely on B. 

careyana for pollen. The fruit is a 3- to 4-sided hairless achene. Pollination 

may be sufficient for high rate of seed production, but the seeds may be 

heavily predated by insects; seed quality and viability are reduced by insect 

damage. Flowers can be subject to frost damage and seed heads are palatable BACA3
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 51

to animals. The filled-seed rate of cleaned seeds collected at Green Ridge 

in 2004 was 49 percent and from seeds sampled directly from seed heads 

in 2005, was 9 percent (range 0–33 percent). The mean number of seeds per 

capitulum in 2005 was 57.2 (21–119). Seed dispersal may be primarily by 

animals. Seeds can be found on the ground near the parent plant; however, 

they may not persist in a seed bank. Like B. sagittata, B. careyana is longlived and able to regenerate vegetatively after fire or other disturbance that 

does not destroy caudex or root crown.

Propagation

Before seeds were collected at the Green Ridge study site, the seedheads 

were checked to be sure fruit had matured and were dry. Dried seedheads 

were harvested by breaking off from stem and crushing them as they were 

placed into a paper bag. The seed heads were left to dry further in the bags 

in the lab for several days before cleaning. A crushing boat or No. 8 circular 

screen (3.2 mm) was used to break up flower heads followed by screening 

with a screen equivalent in hole size to about 5 mm (0.1953 in, 12.5/64) and 

air blown at 18 mm. Screens of various mesh size can be used to remove 

chaff. The screened seeds can be further separated in a South Dakota Seed 

Blower at an air velocity of about 3.5 m/s or other type of air screen or separator. Achenes may show evidence of insects or insect damage and should be 

checked for holes or frass. At a moisture content of 7.8 percent, the number 

of seeds collected at Green Ridge per kilogram was 93,130. Low moisture 

content increases seed longevity; cleaned dry seeds can be stored at 20 o

C 

for up for 5 years; storing at near or below freezing may prolong viability. 

The stratification temperature should be at freezing or as close to freezing as 

possible. Optimum temperatures for germination are reported near those for 

stratification. Seed quality and viability can be reduced by insect damage. 

The viability of tetrazolium-tested study seeds was 79 percent; however, the 

rate of empty and damaged seed differed greatly among lots. 

For large-scale sowing, seeds of Balsamorhiza species can be broadcast 

sown or drilled; however, because seeds are relatively large, they should 

be covered with soil. Sowing in fall or winter is preferable as B. careyana

will germinate in cold soil and near-freezing temperatures. The mean 

germination of study seeds sown at Green Ridge based on accumulated 

emergence was 55.8 percent. Emergence was 7.0 percent in February, and 

by mid March, 44.8 percent. Percentage of surviving seedlings by late May 

BACA3
52 GENERAL TECHNICAL REPORT PNW-GTR-823

was 45.2 percent and the following May, 34.7 percent. Trend in first-year 

emergence and survival is shown in figure A2. By May of the second 

growing season, average length of the hairy basal leaves was 6.5 cm. Aerial 

growth is reported to be slow for this long-lived perennial plant, presumably, 

because much of the growth is being allocated to root growth, and may take 

anywhere from 3 to 8 years before the plant is mature enough to flower. 

Compared to the other 17 species at the Green Ridge site, B. careyana seeds 

had the highest germination; seedlings had among the best survival rates and 

afforded the greatest amount of cover. Seeds of this and other Balsamorhiza 

species are highly recommended for use in a seeding program.

References

Cane (2005), Gilky and Dennis (2001), Hitchcock and Cronquist (1973), 

McWilliams (2002), Rose et al. (1998), USDA FS (1988), USDA NRCS 

(2006), USDI BLM (2003), Young and Evans (1979). BACA3
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 53

Various bees foraging on large, showy flower of Calochortus macrocarpus blooming on Green Ridge, 

eastside Cascades Range.
54 GENERAL TECHNICAL REPORT PNW-GTR-823

Calochortus macrocarpus Dougl. 

Sagebrush mariposa lily

Liliaceae 

CAMA5

Calochortus macrocarpus is a long-lived perennial monocot in the Lily family about 20–30 cm tall. It grows an erect stem from deep-seated, oval bulbs 

with slender, grass-like leaves and is one- to three-flowered. The flower has 

narrow green sepals and three broad, pale pink to lavender petals. The inner 

basal part of the petal has a dark purple band and is moderately bearded 

above the somewhat triangular nectar gland medially located toward the base 

of the petal, three stamens with anthers longer than the filaments; fruit linear 

and three-angled. 

Distribution and habitat

Range extends across the Columbia River plateau from British Columbia 

south to northern California and east to Nevada and northwestern Montana and is found over much of the arid interior of the Pacific Northwest. 

Calochortus macrocarpus occurs in dry prairies or grasslands, sagebrush 

scrub or open Pinus ponderosa forest in well-drained, sandy or rocky soil at 

elevations as high as 2000 m. Palatable to livestock and ungulates. Distribution is increasingly patchy and probably has declined in abundance in grazed 

grasslands and prairies.

Reproductive ecology

Calochortus macrocarpus flowers in late May-June. The species may be 

able to self-pollinate and set fruit, but generally is pollinated by insect 

vectors. The large flowers attract a variety of insects to its pollen and nectar 

located in glands at the base of the corolla; however, they may be successfully pollinated only by large bees such as Bombus species. The fruit is a 

three-chambered capsule. Each chamber may have about a hundred flat, 

round disc-like seeds about 1⁄2 cm in diameter. Fruit set varies from year to 

year but can be > 60 percent. The mean filled-seed rate of the study seeds 

collected at Green Ridge in the east-side central Oregon Cascade Range 

was 90.0 percent in 2004 and 47.0 percent in 2005; mean number of seeds 

per capsule, 44.6 (range 3–122, N = 20). The species does not appear to be 

pollinator limited, but effective seed production fluctuates widely because 

the flowering and fruiting stems are browsed by deer and elk, in some years CAMA5
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 55

so heavily that fruit is rare. Maturity from seedling to a flowering plant 

may take from 3 to 5 years. Some individuals in a population may become 

dormant in response to an environmental condition and not emerge every 

year. This should be taken into consideration when evaluating reintroductions of this species. 

Propagation

Calochortus macrocarpus propagates readily from seed. When mature, 

seeds are disk-shaped, pale, straw-colored, and < 0.5 cm in diameter. Seeds 

are ready to collect in late August–early September from plants at Green 

Ridge on the east side of the central Oregon Cascade Range. After capsules 

are fully mature and beginning to dehisce by splitting starting at the apex, 

the papery seeds are easily collected and poured into paper bags. Seeds 

are relatively free of chaff but need to be blown at about 10 mm to remove 

empty seeds. Number of seeds per kilogram was 377,010. Seed viability by 

tetrazolium testing was 86 percent. 

Stratification is required for ex situ germination; storage at below 

freezing temperatures is recommended. Study seeds from Green Ridge sown 

in late September had germinated before February with peak germination 

in mid March. Seedlings showed leaf damage from insect predation. Some 

seedlings recovered from the clipping and continued to produce leaves. 

Germination based on accumulated emergence was 54.7 percent, and 

survival by May 19 was 37 percent. The seasonal trend in emergence and 

survival is shown in figure A3. By the following May, survival was 24.7 

percent. Emergence rate of seeds sown in a grass-sagebrush steppe in central 

Washington was 55 percent; however, for surface-sown seeds, emergence 

was 6 percent. When precipitation decreases and soil dries in late May, the 

aerial part of the plant senesces, which is characteristic of vernal monocots. 

Leaves averaged 6.5 cm and were longer in the second year than the first. 

However, for this large, liliaceous monocot, it may take from 3 to 5 years to 

produce a flowering plant from seed. Although some Calochortus species 

may be propagated from bulbs, the propagules of most do not successfully 

transplant from the wild. Collecting bulbs or flowering stems in the wild is 

discouraged or illegal because it destroys the entire plant. 

References

Durham and Sackschewsky (2004), Gardenbed (2004), Hitchcock and Cronquist (1973), Kruckeberg (1982), Miller et al. (2004), USDA NRCS (2006). 

CAMA5
56 GENERAL TECHNICAL REPORT PNW-GTR-823

Erigeron filifolius (Hook.) Nutt. var. filifolius

Threadleaf fleabane

Asteraceae

ERFIF

Erigeron filifolius var. filifolius is a tall (10–50 cm), perennial herb with 

a taproot and many stiff, hairy branching stems and narrow, linear leaves 

(0.3–3.0 mm wide). Inflorescence may have single to multiple flower heads 

(1–4) with ray flowers (15–75) that are blue to pinkish white and 3–13 mm 

long; fruits are achenes with pappi and sparse hairs. 

Distribution and habitat

The species ranges from British Columbia through eastern Oregon to 

the east side of the Cascades and south to northern California and east to 

Nevada and Wyoming. It occurs in sagebrush and dry forests, in plains and 

foothills at elevations 1200–2000 m. Adapted to dry, rocky, or sandy soil, 

and lava beds, it is associated with Purshia tridentata, Artemesia species, 

Juniperus species, and Pinus ponderosa. 

Reproductive ecology

Erigeron filifolius flowers from June through August. Small generalist pollinators such as solitary bees and syrphid flies foraging for nectar and pollen 

visit the composite flowers. Erigeron species is also visited by wasps and 

butterflies attracted to the nectar. Some Erigeron species may be self-fertile; 

however, this species requires an insect vector for successful seed set, but 

may self-pollinate as well. Of the study plants from Green Ridge on the 

east-side central Oregon Cascade Range, the average number of achenes per 

seed head in 2005 was 134; mean rate of filled seed was 45.0 percent in 2004 

and 11.6 percent in 2005. In both years, E. filifolius seeds showed evidence 

of predation. 

Propagation

Seeds are collected at Green Ridge on the east side of the central Oregon 

Cascade Range from late July through mid August. Seeds remain in collection bags; each bag is inspected so as to avoid contamination of damaged or 

infested seeds. When the seeds are ready for collection from the seed heads, 

the pale and feathery pappi are highly visible, and along with the achenes ERFIF
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 57

are easily removed by hand without pulling off the seed head. Achenes are 

crushed using a crushing boat to de-hair seeds and screened with 0.0833-in 

(1/12) mesh screen. Seeds are air blown at 10 mm, then 13 mm, and screened 

again with 0.0833; repeat process if seeds still have pappi attached. The 

seeds are very tiny; number of seeds collected at Green Ridge per kilogram 

was 5.3 million at 7.2 percent moisture content. Mean seed viability of two 

seed lots was 85 percent, and mean rate of in vitro seed germination (no 

stratification) 35.3 percent. Stratification at almost freezing temperatures 

might increase germination rate. Mean germination of seeds sown in

September at Green Ridge based on accumulated emergence was 11.0 percent; survival by late May was 1.4 percent. For trend in emergence and 

survival see figure A4. Frost heaving of soil in early months may have 

contributed to poor emergence rate. Two-year survival was 1.2 percent with 

little or no aerial growth; height was < 1 cm. This species germinated very 

early in spring at near-freezing temperatures, but the small seeds are vulnerable to frost heaving. Grows best in full sun; drought tolerant.

References

Gilky and Dennis (2001), Harmond et al. (1968), Hitchcock and Cronquist 

(1973), Parkinson (2003), USDA NRCS (2006), USDI BLM (2003). 

ERFIF
58 GENERAL TECHNICAL REPORT PNW-GTR-823

Eriogonum umbellatum Torr.

Sulphur-flower buckwheat

Polygonaceae

ERUM

Eriogonum umbellatum is a low-growing branching perennial herb or semishrub from a strong taproot with branching crown. Stems prostrate, branching and mat forming or erect; leaves variable oblong to oval or spatulate. 

The species is highly variable in its vegetative and floral characters. The 

inflorescence is simple to compound umbel of dominantly light-yellow

flowers borne on a short axis surrounded by a greenish campanulate involucre on slender pedicels. Perianth cream or yellow, becoming accented with 

shades of orange or pink. Flowers are often imperfect. Three styles bear a 

one-celled ovary and single ovule. Fruit is a smooth, three-angled, achene.

Distribution and habitat

Range from southern British Columbia south to California east of the

Cascade Range, east to Montana and Wyoming, and south to Arizona. 

Mostly occurs in sagebrush steppe, dry prairie or alpine rocky ridges, mountain slopes from sea level to subalpine elevations. Occurs in dry open areas 

under full sunlight, with minimal rainfall and rocky to sandy, moderately 

coarse, well-drained soil. Associated with Artemesia, Purshia, and bunchgrasses in dry Pinus ponderosa associations. 

Reproductive ecology

Flowering from May through August, depending upon topography and 

variation in climate. Maximum seed set is dependent on insect pollination, 

although autogamy may occur. Pollen and nectar attract wasps, bees, and 

other insects. For each flower, a hard, dry, single-seeded achene is produced. 

Achenes mature in 6–8 weeks. Birds and small mammals (quail, deer, 

grouse) consume the seeds. May be host to caterpillars of a copper butterfly 

(Lycaena gorgon) known to lay eggs on flower stems of Eriogonum species. 

A single umbel may have many seeds, but the rate of filled seeds may be low 

and vary greatly among lots and years. In 2004, the mean filled-seed rate of 

study seeds originating from Green Ridge on the east-side central Oregon 

Cascade Range was 71.7 percent and in 2005, 17.3 percent. ERUM
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 59

Propagation

The dry, papery umbels are collected at Green Ridge from late July 

through August and placed into paper bags. Mature seeds (pappus visible) 

are easily removed by hand without pulling off the seed head. Seed heads 

are crushed with a crushing boat or by hand, screened with 4 by 30 mesh 

(0.0203-in) screen, and air blown at 30 mm. Screen with No. 10 Westrup 

screen or repeat with 0.188 or 1/16 hand screen or 0.1094-in round screen 

and 0.0203-in screen to aid stem removal (Harmand et al. 1968). Because the 

percentage of filled seed may be low, cleaning requires repeated screening 

and blowing to rid seed of flower chaff and separate the empty from filled 

seed. The number of study seeds collected at Green Ridge per kilogram 

was 291,000 at 8.8 percent moisture content. Germination rate of 86 percent 

was reported on unstratified seeds from Ada County, Idaho, and seedling 

survival under greenhouse conditions was 52 percent. The mean viability 

of the study seeds from Green Ridge based on tetrazolium testing was 

72.5 percent; germination rate of unstratified seeds on moist filter paper 

was 37.2 percent with 42.4 visibly moldy. Stratification requirements vary 

greatly depending upon origin of seed. Usually the higher the elevation the 

more stratification required. At the Green Ridge study site, seeds began 

germinating early under cold soil conditions. Emergence in early February 

2005 was 9.6 percent. Germination based on accumulated emergence was 

34.5 percent with germination peaking roughly in mid March. See figure A5 

for trend over one growing season in emergence and survival. Seedlings are 

morphologically adapted to cold and high solar irradiance but are susceptible 

to damping-off fungi and insect herbivory (see photo). Mean survival was 

21.6 percent in May at the end of the first growing season and the following 

year, 11.3 percent. Average height was 2.3 cm by May of the second year, 

and contribution to herbaceous cover was low. Approximately 0.2 lb of seeds 

collected at Green Ridge and sown in fall for growout at Lucky Peak Nursery, Boise, Idaho, yielded 25.0 lb in 2 years and about 5.5 lb of seed the year 

following (appendix 1).

References

Archibald (2006), Gilky and Dennis (2001), Harmond et al. (1968),

Hitchcock and Cronquist (1973), Parkinson (2003), Parkinson and DeBolt 

(2005a), Rose et al. (1998), USDA NRCS (2006). 

ERUM
60 GENERAL TECHNICAL REPORT PNW-GTR-823

Eriophyllum lanatum (Pursh) Forbes

Common woolly sunflower

Asteraceae

ERLA6

Eriophyllum lanatum is a perennial herb or subshrub 10–40 cm tall, several 

stemmed, with woolly leaves alternate and variable from entire to ternate. 

Heads radiate with few ray flowers, involucre with two series of bracts, disk 

flowers few to many, perfect; ray flowers 8–13, yellow (1–2 cm). Achene, 

slender, four angled. Variable species morphology with numerous varieties.

Distribution and habitat

Eriophyllum lanatum ranges from British Columbia to California and east to 

Montana and Utah. It occurs in low to mid elevation in prairies and mountainous dry forests. Eriophyllum lanatum grows well in dry, open slopes or 

rocky outcrops and occurs on hillsides or lowlands in well-drained soil. 

Reproductive ecology

Eriophyllum lanatum is an outcrossing species that exhibits considerable 

polyploidy. Polyploidy can give rise to ecotypes that may be specifically 

adapted to environmental conditions. Eriophyllum lanatum flowers from 

April through May. The foliage and buds appear to exude a substance before 

flowers open that is highly attractive to flies. Flies visit the plant before the 

flower opens and appear to be feeding on a sticky exudate from the calyx. 

The flowers are visited by a variety of insects for pollen and nectar but flies 

were the most constant visitors. The mean number of seeds collected from 

the capitula was 75 (N = 8, range 57–86); mean rate of filled seed in 2004 

was 71.0 percent and in 2005, 57.8 percent.

Propagation

At the Green Ridge site on the east-side Oregon Cascade Range, seeds are 

collected when the seed heads are dry and petals shriveled in late August. 

One way to collect seeds is to remove seed heads with scissors below the 

calyx, which is less destructive than removing by hand. Seed heads placed 

in paper bags can remain in bags in the lab for further drying. If seed heads 

are sufficiently dry, the seeds readily fall out of the receptacle when touched 

or shaken into paper bags. Insect predation of the achenes does occur with ERLA6
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 61

this species. However, we found less insect predation of E. lanatum achenes 

at the Green Ridge site than at a site in the central Willamette Valley-Coast 

Range foothills. Seeds were cleaned in the Westrup machine with No. 10 or 

12 screen followed by air blowing at 20 mm. Seeds cleaned the following 

year were also screened sequentially with 3/64 by 5/16, 18/20, 20/20 for seed, 

and 36/36 for dust, and air blown at 16-18 or 22 mm. The number of cleaned 

seeds per kilogram was 1,387,900 at 5.6 percent moisture content. Mean 

viability of two cleaned seed lots by tetrazolium testing was 59 percent. 

Seeds sown at Green Ridge in late September 2004 emerged in early 

March 2005 when diurnal soil temperatures began to rise to above freezing. 

The germination rate based on accumulated emergence of seedlings was 16.9 

percent. By the end of May, seedling survival was 13.9 percent and was 5.9 

percent by May of the following year. The trend in emergence and survival 

in first growing season is shown in figure A6. Average height was 3.1 cm; 

however most growth is through lateral branching. Cover was maintained 

from 2005 to 2006 owing to vegetative spread of surviving seedlings. This 

species grows and matures rapidly and provides excellent cover because of 

its spreading habit as shown in photo of an E. lanatum subplot at the Green 

Ridge study site. This species is productive also in a nursery setting. At the 

Lucky Peak Nursery, Boise, Idaho, 0.1 lb of seed yielded 32.0 lb of seed in 

the second growing year.

References

Archibald (2006), Gilky and Dennis (2001), Harmond et al. (1968), Hitchcock and Cronquist (1973), Parkinson (2003), Rose et al. (1998), USDA 

NRCS (2006), USDI BLM (2003), Vance et al. (2006). 

ERLA6
62 GENERAL TECHNICAL REPORT PNW-GTR-823

Linum lewisii Pursh

Lewis flax

Linaceae

LILE2 

Linum lewisii is a short-lived perennial herb or subshrub having a semiwoody rootstock producing one or several stems 10–70 cm in height. The 

inflorescences are cymose with five-petaled flowers pale to nearly white 

to sky blue. The homostylous flower has five petals and five fused carpels, 

each with two ovules.

Distribution and habitat

Linum lewisii ranges throughout western North America from Alaska to 

New Mexico. It occurs in a range of habitats from prairies and shrub steppe 

to dry forests and alpine ridges on open or partly shaded sites with generally 

dry, well-drained soil. 

Reproductive ecology 

Linum lewisii is an obligate outcrosser. Flowers are produced throughout 

summer and early autumn, and each flower opens in the morning and 

blooms for a single day. The species attracts bees and flies, which are 

attracted to both nectar and pollen. The most common visitors at high elevation in Colorado are small solitary bees and muscoid flies although syrphid 

flies and rarely Bombus species were reported carrying Linum pollen. At the 

Green Ridge site on the east-side central Oregon Cascade Range, small flies 

and solitary bees were observed visiting the flowers. The fruit are round 

capsules each containing two seeds. Reproductive success was high. In 2 

years of sampling and cutting seed, we never found one that was not filled. 

Linum lewisii seeds have a complex and conditional dormancy (see Meyer 

and Kitchen 1994). Meyer and Kitchen reported that variable germination 

responses in the field for seeds from the same origins, whether in the fall, 

spring, or the following year may depend on environmental conditions 

interacting with the seeds’ dormancy response allowing this native flax 

species to be highly adaptable to the variable conditions of the montane and 

high plateau regions of the Western United States. LILE2
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 63

Propagation

Racemes of L. lewisii are grasped below the seed heads and tipped into 

paper bags or buckets. Mature seeds readily fall from the capsules into the 

container and clean easily. For complete cleaning, crush capsules to release 

seeds, hand screen with 0.087-in (1/12–1/14) screens and air blow. The 

number of seeds per kilogram was 334,610 at a 6.9 percent moisture content. 

The mean filled-seed rate was 100 percent. Seed dormancy is highly variable 

and will differ among sources. Linum lewisii can be seeded in early spring 

but recommend seeding in late fall. Seeds sown in late September at Green 

Ridge on the east side of the central Oregon Cascade Range germinated 

in early March when soil temperatures were near freezing and while soil 

retained moisture. The mean germination based on accumulated emergence 

was 34.3 percent; peak emergence was in early April, and by late May, survival rate of seedlings was 29.4 percent as shown by trend line in figure A7. 

In May the following year, survival was 25.6 percent. However, new seedlings emerged in over half the plots (1–8 per plot). Average height in 2006 

was 8.2 cm (1.4–24.6 cm). Large variation is because of bolting of maturing 

plants and new recruitment in 2006. Individuals that reached maturity and 

flowered in 2006 averaged about 25 cm in height. Average vegetative cover 

was 4.4 percent in 2005 and rose to 12.7 percent in 2006 because 20 percent 

of the plants had bolted and flowered. In a nursery environment with ample 

water and fertilizer, fall-seeded L. lewisii can produce flowers within a 

single growing season. The yield of seeds from 0.1 lb of seed sown at Lucky 

Peak Nursery, Boise, Idaho, was relatively low; plants produced only about 

0.55 lb of seed in the second year and none the third year. Seeds of this species have been shown to have variable dormancy and widely variable germination rates. More studies are needed on this species, as it is excellent for a 

seeding program because of its rapid growth, maturity, and low mortality.

References

Hitchcock and Cronquist (1973), Kearns and Inouye (1994), Meyer and 

Kitchen (1994), Pendleton et al. (2008), Reeves (2006), USDA FS (1988), 

USDA NRCS (2006).

LILE2
64 GENERAL TECHNICAL REPORT PNW-GTR-823

Lomatium triternatum (Pursh) Coult. &

Rose

Nineleaf biscuit root 

Apiaceae

LOTR2

Lomatium triternatum is a perennial forb/herb; stems usually solitary 

20–80 cm tall, from a simple or sometimes branched crown on an elongated 

taproot. Leaves are mostly basal and cleft several times, each leaf cleft into 

three long, narrow leaflets, up to 10 cm long. Inflorescence is a bractless, 

compound umbel with small clusters of yellow flowers, bracts green. Fruits 

are schizocarps, oblong to elliptic, flattened, with papery side wings, two 

flat, ribbed seeds. 

Distribution and habitat

Range is from British Columbia and Alberta to Colorado, Utah, and

California. One of the most common and widespread plants found in a 

scattered distribution in plains and foothills on open slopes in P. ponderosa

forest types. Scattered and locally common at low to mid elevations but can 

be found at elevations as high as 3000 m (10,000 ft) in Wyoming. Lomatium 

triternatum prefers well-drained soil and full sun to partial shade. 

Reproductive ecology

The hermaphroditic flowers depend on pollinators for seed set, and are a 

source of pollen and possibly also nectar to insects, particularly solitary 

bees, wasps (such as the cuckoo wasp shown on the umbel) and syrphid 

flies. The mean number of Green Ridge seeds per umbel was 69 (range 

31–262, N = 20); mean rate of filled seeds was 73.3 percent in 2004 and 86.5 

percent in 2005 indicating pollination is effective. However, fruits and seeds 

may be predated by weevils which are patchily distributed within a large 

population of L. triternatum. 

Propagation

Fruit and seeds of L. triternatum are ready for collecting when they no 

longer feel waxy to the touch. Lomatium triternatum is typically scattered 

and not abundant in any one area. Seeds are removed by running fingers 

upward along the stem and pulling gently. Seeds are placed in paper bags 

and brought inside for further drying. Seeds were cleaned by hand screening LOTR2
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 65

and blowing off any chaff. The number of cleaned seeds per kilogram of 

seeds collected from Green Ridge in Jefferson County, Oregon, was 145,160 

at a moisture content of 7.9 percent. Viability of cleaned seeds using tetrazolium testing was 77 percent. In vitro germination of stratified seeds was 

only 16 percent with a low percentage of moldy seeds; many seeds germinated while in stratification. Seeds from Malheur County, Oregon, also 

were germinated in the dark under stratification at 4 °C; under greenhouse 

conditions, survival was 53 percent. Germination based on accumulative 

emergence of seeds collected and grown at the Green Ridge study site on the 

east-side Oregon Cascade Range, was 70.8 percent with seedling survival by 

May, 45.1 percent. The trend in emergence and survival is shown in figure 

A8. Survival 1 year later was 35.8 percent, and average height of surviving 

seedlings was 10.1 cm (6.2–14.2 cm). The tallest plants bore flowering stems. 

This is a cold-season species in which germination of the Green Ridge study 

seeds was already > 35 percent by early February (when soil temperatures 

were usually at or below freezing) reaching its peak by mid March. Others 

have reported that stored seed can be rather slow to germinate; however, 

this was one of the 3 out of 18 study species at Green Ridge that in some 

instances matured to flowering in the first year.

References

Gardenbed (2004), Hitchcock and Cronquist (1973), Parkinson and

DeBolt (2005b), Thompson and Pellmyr (1989), USDA FS (1988), USDA 

NRCS (2006). 

LOTR2
66 GENERAL TECHNICAL REPORT PNW-GTR-823

Lotus crassifolius (Benth.) Greene

Big deervetch

Fabaceae

LOCR

Lotus crassifolius is a rhizomatous, perennial herb or subshrub. Growth form 

from semi-prostrate to upright, up to 1 m tall, erect to spreading, and branching. Leaves are pinnately compound with 5–15 oblong leaflets. Inflorescence 

an umbel with 7–20 flowers on short pedicels, flowers white or greenishyellow tinged with reddish purple; fruit dehiscent, elongated legume, 2–5 cm 

long, with 4–20 dark brown, round seeds. 

Distribution and habitat

Ranges from northwest Washington to southern California and in the

Cascade Range from low to middle elevations. Occurs in scattered stands. 

Common habitat may be dry to mesic in P. ponderosa associations and 

mixed coniferous forests along streambanks or in open areas with deep 

Well-drained soil. 

Reproductive ecology

Flowers bloom May-July. Nectar and pollen attract bees. Legumes mature 

from mid-July through August at Green Ridge on the east-side central 

Oregon Cascade Range. Pods twist spirally at maturity and halves split 

with force expelling seed. The seeds are hard, round, and about 20–30 mm 

in diameter. The mean number of Green Ridge seeds per legume was 10.8 

(range 4–20, N = 20) and mean rate of filled seeds was 60.3 percent. Fruits 

and seed coats were visibly damaged by insects; however, examination of 

cut seeds indicated that predation did appear to affect the endosperm or 

embryo. Lotus seeds reported to have been partially eaten by a weevil seed 

predator were tested for viability, and subsequent seedling vigour and a large 

proportion of the damaged seeds were found to be viable. Like other species 

in the Fabaceae family, seeds require scarification as well as stratification 

for best germination. Perhaps the weevil acts as a scarifier. Lotus crassifolius

also reproduces vegetatively from rhizomes following wildfire or other 

disturbances. LOCR
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 67

Propagation

Seeds are collected when fruit appears reddish tan and dry to the touch. The 

mature legumes are removed from the plant or broken into paper bags held 

below the plants. Seeds are easy to clean and can be readily cleaned by hand 

or with the help of Westrup machine and No. 5 screen. An air blower at 5 

mm can be used to separate chaff, if necessary. The number of clean seeds 

per kilogram of seeds collected at Green Ridge was 88,230 at a moisture 

content of 7.9 percent. The mean viability of seeds of all three lots was about 

95 percent. 

Lotus crassifolius seeds benefit from stratification and should be fall 

planted so they can stratify in situ. We investigated whether scarification and 

using a soaking time longer than 24 h would also help in vitro germination. 

Scarification (light sanding of seed coat) and 10-week stratification with a 

24- or 48-h soak significantly improved seed germination (42.6 percent vs. 

< 30.0 percent). Scarification and soaking does not help germination if seeds 

are not stratified, as germination of unstratified seeds was < 0.5 percent 

even with those additional treatments. 

Lotus crassifolius seeds sown in late September at the Green Ridge 

study site began germinating in mid March when minimum soil temperatures and average air temperatures were above freezing. Germination based 

on accumulated emergence was 22.4 percent. Emergence increased from 

March through May as shown by the trend curve in figure A9. Survival 

in late May was 21.7 percent. Survival in May the following year was 1.1 

percent. The drastic drop in survival appeared to be primarily caused 

by insect herbivory as shown in photo of L. crassifolius seedling in plot. 

Because of the drastic drop in number of viable seedlings, average height 

of this normally fast-growing, herb was only 2.0 cm in the second year, and 

cover declined to 0.4 percent indicating that L. crassifolius seedlings were 

seriously affected by insect predators. Lotus crassifolius seeds from Green 

Ridge, Deschutes National Forest sown at the Lucky Peak nursery grew 

rapidly and increased seed yield from 0.4 lb to 15.5 lb in 3 years, an increase 

of > 3,700 percent. This species has excellent potential to produce cover and 

occupy a site under conditions where herbivory does not severely impact 

seedlings.

References

Flessner and Darris (2001), Hitchcock and Cronquist (1973), Ollerton and 

Lack (1996), USDA FS (1988), USDA NRCS (2006). 

LOCR
68 GENERAL TECHNICAL REPORT PNW-GTR-823

Olsynium douglasii (A. Dietr.) Bickn.

Douglas’ grass widow

Iridaceae

OLDOD

Olsynium douglasii is a rhizomatous, perennial monocot with stems 10–30 

cm tall; often found in clumps with narrow but flattened grass-like leaves 

rarely more than 10 cm long, sheathed at the base. Perianth of flower is a 

deep reddish purple with 6 tepals up to 3 cm long, three stamens fused at 

base with bright yellow anthers. The ovary is inferior; fruit are three-celled 

somewhat globose capsules up to 1 cm long with several seeds per cell. 

Seeds are about 1.5–2.5 mm, brown, angular and pitted. Olsynium douglasii

var. inflatum is often lighter in color with wider perianth and more inflated 

filament tube at base than var. douglasii. 

Distribution and habitat

Olsynium douglasii ranges from British Columbia south along both sides of 

the Cascade Range to California and along the Columbia River gorge, east 

to Idaho and Utah. Occurs from near sea level to about 1800 m, in prairies 

and dry western forest types including pine and oak woodlands, also in dry 

sagebrush and juniper steppe. A cool-season plant that prefers open areas 

where there is sufficient moisture in the spring. 

Reproductive ecology

Olsynium douglasii is the only member of the genus found in North America 

and the only one that offers nectar in addition to pollen. It flowers from 

February through June depending upon elevation. The flowers tend to be 

ephemeral opening for a few hours. Bombus and Osmia species as well as 

other species of solitary bees visit the flower for nectar and pollen. Because 

pollinating insects rely on nectar for energy in early spring, O. douglasii may 

be an important energy source. The mean filled-seed rate of seeds collected 

from Green Ridge on the east-side central Oregon Cascade Range was 89.0 

percent indicating pollination was effective. OLDOD
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 69

Propagation 

Seeds are collected by tipping the dried and dehiscent capsules into paper 

bags without removing the capsules or the plant from the ground. Seeds 

empty into the bag easily without much chaff. Hand screening may be all 

that is needed to clean seed. The number of dry, cleaned seeds per kilogram 

was about 293,460; moisture content was not determined. Seed viability of 

the single Green Ridge seed lot was 79 percent. The germination rate of the 

study seeds on Green Ridge based on accumulated emergence was about 45 

percent. The germination rate was higher than that reported by Kruckeberg 

(1982) who described seed germination as “dependably low” (10 to 20 

percent). Seeds began to germinate in the field in early March. Germination 

was rapid, peaking by mid April. See figure A10 for trend in emergence and 

survival. Germination based on accumulated emergence was 45.0 percent 

and mean survival by late May was 29.8 percent. Mean survival in May the 

following year was 22.3 percent and average leaf length was 6.2 cm. Each 

seedling consisted of one, or possibly two, slender, grass-like leaves. The 

leaves had senesced by June when precipitation is low and the temperature 

elevates. No plants reached maturity. This species would not be used to 

increase vegetative cover but for its attractiveness to early spring pollinators 

and functional ability to grow with graminoids and broad-leaved plants. 

Vegetative propagation using offshoots from rhizomes has not been tested on 

a large scale but may be an option for increasing seed plants as they reportedly transplant well.

References

Gilky and Dennis (2001), Goldblatt and Manning (2009), Hitchcock and 

Cronquist (1973), Kruckeberg (1982), Legler (2006), USDA NRCS (2006).

OLDOD
70 GENERAL TECHNICAL REPORT PNW-GTR-823

Penstemon humilis Nutt. ex Gray 

Low beardtongue

Scrophulariaceae

PEHU

Penstemon humilis is a perennial herb about 10–60 cm tall with entire, 

lanceolate leaves up to 12 cm long and basal leaves tufted and persistent; 

inflorescence one or a few flowers, five-segmented calyx, the tips slightly 

purple, the corolla hairy, blue-purple. Pollen sacs glabrous opposite and dark 

and bearded staminode; inferior ovary; capsule length, 4–6 mm; seeds, 1–1.5 

mm long.

Distribution and habitat

Range west of the Continental Divide from Washington to California, east 

to western Wyoming and Colorado. Species occurs on open, rocky and 

depauperate slopes in sagebrush prairies and valleys and dry open forests. 

Often found on road cuts along unpaved roads in Pinus ponderosa/Purshia 

tridentata/Festuca idahoensis associations. 

Reproductive ecology

The small flower with its deep blue corolla and nectar glands attract moths 

and long-tongued bees such as the native leaf cutter bee (Megachilidae) 

shown in photo. Each capsule contains two dozen or more seeds. Little 

predation was observed of 60 sampled and cut seeds collected from Green 

Ridge for study; mean filled-seed rate was 83.3 percent. Flowering occurs 

from May through July; seeds mature about 6–8 weeks later. Seed distribution may be by animals or water, although rodents and birds eat seeds. 

Propagation

Seeds are collected by carefully tipping the dried racemes with ripe fruit into 

paper bags without removing the dry capsules from the stem or pulling the 

plant from the ground. Seeds empty into the bag easily without much chaff. 

The small, hard seeds are easily cleaned by screening and may be air blown 

at 10 mm if needed. The number of seeds per kilogram of study seeds from 

Green Ridge on the east-side central Oregon Cascade Range was 4,822,100. 

Seed viability based on tetrazolium testing was 88 percent; mean in vitro 

germination rate of unstratified seeds was 37.2 percent with 42.4 percent of 

seeds eventually becoming moldy. Dry seeds in cold storage are reported to PEHU
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 71

retain their viability well. Germination based on accumulated emergence of 

study seeds sown in late September at Green Ridge was 18.3 percent. Peak 

emergence occurred in late April. See figure A11 for trend in emergence 

and survival over the first growing season. Attrition resulted in 10.6 percent 

survival by late May, and by May the following year, 0.8 percent. Low 

survival appeared to be due in part to frost heaving that buried tiny seeds or 

displaced them to the soil surface where high soil surface temperatures may 

have also contributed to mortality. Cover was < 1 percent and height was 

observed to be ≤ 1 cm. This species may require more seeds under nursery 

rearing conditions. Other Penstemon species have reportedly been successfully propagated, but differences in dormancy among seed sources can be 

critical in this species.

References

Clinebell and Bernhardt (1998), Gilky and Dennis (2001), Hitchcock and 

Cronquist (1973), Lodewick and Lodewick (1999), Meyer et al. (1995). 

PEHU
72 GENERAL TECHNICAL REPORT PNW-GTR-823

Silene douglasii Hook. var. douglasii

Douglas’ silene

Caryophyllaceae

SIDOD

Silene douglasii var. douglasii is a caespitose, perennial herb 10–40 cm 

tall with linear-lanceolate leaves grouped at the base, a stout taproot and 

branching caudex. Stems are simple or few-branched with several pairs of 

sessile leaves at intervals up the stem. The inflorescence is cymose with 

axillary and terminal, white to pink flowers, calyx five-lobed, 10-nerved and 

tubular; petals five, bi-lobed and curl inward toward the end of 4–5 days of 

flowering; flower has 10 stamens and 3–4 styles. The fruit is a single-celled 

capsule, seeds 1–2 mm long, ovoid to round and brown, having rugose or 

bumpy surface with rounded papillate margins. 

Distribution and habitat

Range from British Columbia south through Cascades to Sierra Nevada in 

central California, east to northern Utah, Nevada, and western Montana. 

Occurs in moist microsites in sagebrush steppe and prairie, and dry, montane 

forests on slopes and valleys under partial canopy. 

Reproductive ecology

Silene douglasii is a source of pollen and nectar attracting the noctuid moth 

Hadena variolata, but also syrphid flies and halictid bees. Seedling recruitment is low as indicated by the low abundance and infrequent clusters of S. 

douglasii distributed throughout the collection area. Seed germination was 

significantly better in seeds produced from cross pollination than from self 

pollination. Pollinators are important to fecundity, but pollinating moths of 

genus Hadena also oviposit in flowers and their larvae predate capsules. 

Interestingly, the seeds from capsules with the highest number of seeds 

collected from Green Ridge on the east-side central Oregon Cascade Range 

were more likely to be empty. Some seeds had holes in them and probably 

had been predated by larvae. Predation by noctuid moths is common in other 

Silene species and may stimulate new flowering. The mean number of seeds 

per capsule was 51.7 (range 20–95, N = 20). The filled-seed rate of seeds 

collected from capsules in 2005 was 78.0 percent. SIDOD
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 73

Propagation

Dried seeds of the plant were collected at Green Ridge by tipping over the 

fruited stalks into paper bags without removing the capsules or the plant 

from the ground. Mature seeds from dehiscent capsules emptied into the bag

easily without much chaff. In the lab, capsules were crushed releasing seeds 

onto a hand screen followed by air blowing. The small seeds numbered about 

1.5 million seeds/kg or 692,591/lb; seed moistue content was 9.3 percent. 

Seed viability was high (90 percent) based on standard tetrazolium tests. 

Seeds will germinate in cool temperatures with germination occurring by 

early March when mean soil temperature was about 5 oC. Germination 

based on accumulated emergence of seeds sown the previous September 

was 23.1 percent. Survival was 12.7 percent and 1 year later was 4.1 percent. 

See the trend in emergence and survival in the first growing year shown in 

figure A12. Cover was less than 2 percent both years and measurable height 

the second year averaged 2.7 cm. This species grew slowly under the conditions of the site but it may be a slow-growing species. Domestic species are 

known to grow readily from seed. Seeds from the wild S. douglasii also can 

be greatly increased in a nursery setting. Seeds collected at Green Ridge 

were sown at the Lucky Peak Nursery, Boise, Idaho, resulting in 0.08 lb of 

seed yielding 13.5 lbs of seed the second year after sowing and 0.5 lb the 

third year for a total increase of >17,000 percent. Mature plants of other 

Silene species also have been propagated through division and cuttings. 

Silene douglasii needs to be monitored beyond 2 years, as it provides excellent cover at maturity and appears to be a relatively long-lived species that 

maintains itself through sprouting new shoots from a branching caudex.

References

Burgett et al. (1989), Hitchcock and Cronquist (1973), Kephart et al. (2006), 

Kruckeberg (1982), Lofflin and Kephart (2005), Pettersson (1991), USDA 

NRCS (2006), Wright and Meagher (2003). 

SIDOD
74 GENERAL TECHNICAL REPORT PNW-GTR-823

Zigadenus venenosus S. Wats.

Meadow death camas

Liliaceae

ZIVE

Zigadenus venenosus is a cool-season, perennial monocot; grows from an 

oval bulb, stem 20–70 cm tall. Leaves mostly basal, grasslike, 10–30 cm 

long. Inflorescence an upright raceme with creamy-white tepals, campanulate flowers. Hypogynous with capsule 8–15 mm long, seeds light brown, 

5–6 mm long. 

Distribution and habitat

Ranges from British Columbia south to Baja California east to Alberta and 

south to Colorado. Grows in open forests and forest edges, meadows and 

rocky or grassy slopes usually at 400 to 3500 m elevations in a variety of 

soils from clay textured to gravelly or rocky. This species is often common 

in the ponderosa pine-bunchgrass plant communities. 

Reproductive ecology

Zigadenus venenosus may require 2–3 years to attain sexual maturity.

Flower parts persist until the capsule dehisces and seeds are dispersed. The 

flower requires an insect vector to produce viable seed. Despite that, Z. 

venenosus contains zygacine, putatively toxic to mammals and most bees. 

Adults of the generalist solitary bee, Osmia lignaria (Megachilidae), were 

paralyzed and soon after died when experimentally fed zygacine, which may 

explain the lack of native bee generalist pollinators visiting Zigadenus species. Zigadenus is pollinated by the solitary bee Andrena astragali, known 

as the death camas bee because it uses only Zigadenus pollen to feed itself 

and its progeny. Capsules and seeds are predated as shown in photo. The 

filled-seed rate was 82.2 percent of seeds sampled from the collection bags; 

some seeds were empty but none showed damage. 

Propagation 

Seeds mature from mid July through late August. To collect seeds, the dried, 

dehiscing racemes are snipped or carefully broken off by hand and placed 

into paper bags without removing the capsules. Seeds empty into the bag 

easily without much chaff. A crushing boat is used to break up flower heads 

and release seeds. Seeds are screened with 0.1641 (101/2) screens, then air ZIVE
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 75

separated with a blower at 18–25 mm max. Cleaned seeds per kilogram of 

study seeds from east-side central Oregon Cascades Range was 285,770. 

Five seed lots from different zones within the collection area were tested for 

viability; mean viability was 86 percent (74–92 percent). Seeds germinated 

during the 10 weeks in stratification confounding the in vitro germination 

test; no unstratified seeds germinated. Some of the seeds sown at Green 

Ridge in the fall had germinated before mid February indicating tolerance

of cold soil and air temperatures. Germination of study seeds sown at 

Green Ridge based on accumulated seedling emergence was 44.2 percent; 

survival of emergent seedlings by late May was 32.7 percent. See figure 

A13 for trend in emergence and survival in the first growing year. By May 

the following year, survival was 25.6 percent and average leaf length of 

surviving seedlings was 5.8 cm. Zigadenus may be propagated vegetatively 

also by carefully extracting bulb offsets from its bulb located about 5–20 cm 

underground. 

References

Cane et al. (2004), Gilky and Dennis (2001), Hitchcock and Cronquist (1973), 

Howard (1992), Tepedino (2003), USDA NRCS (2006).

ZIVE
76 GENERAL TECHNICAL REPORT PNW-GTR-823

Achnatherum thurberianum (Piper) Barkworth

Thurber’s needle grass

Poaceae 

ACTH7

Achnatherum thurberianum is a strongly tufted perennial, bunchgrass with 

culms, 30–60 cm tall, sheath glabrous, ligules 3–6 mm, blades 10–25 cm 

long, filiform and involute. Inflorescence is a long, narrow panicle having 

few flowers. Glumes are 9–14 mm long, floret 7–9 mm, lemma 8–9 mm and 

awn 4–5 cm long, jointed with hairs 1–2 mm long on lower joints. Fruit are 

caryopses.

Distribution and habitat 

Range from Washington and Oregon east to central Idaho and southwestern 

Montana, south to Nevada and central California; occurs on grassland 

prairies, open coniferous forest, sagebrush steppe on rocky slopes. Associated with Pinus ponderosa, Juniperus spp. and Festuca idahoensis and 

Pseudoroegnaria spicata where it is a common subordinate of those grass 

communities. The species is better adapted to, and can be the dominant 

grass in, warmer and drier sites. One of the most drought-tolerant species, A. 

thurberianum grows in warm soil and in sagebrush habitat, and is typically 

the dominant grass in the driest sites. However A. thurberianum generally 

recovers slowly following wildfire and may have reduced vigor. Competitive 

perennial and annual grasses, especially the invasive exotic, Bromus tectorum, which is a highly successful competitor of A. thurberianum, seedlings 

can inhibit its postburn reestablishment. 

Reproductive ecology

Achnatherum thurberianum flowers from May through June and is wind 

pollinated. Seeds disperse to provide new recruits, and tillering vegetatively 

expands the existing plant; however, if root crown is burned, A. thurberianum will only reproduce by seed. A. thurberianum is not as adapted to cold 

soil, and to germinate, it requires higher soil and air temperatures than either 

Festuca idahoensis or Pseudoroegnaria spicata. The filled-seed rate of seed 

collected from Green Ridge was 60.0 percent in 2004 and 61.6 percent in 

2005. However seed production has been reported as generally low. ACTH7
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 77

Propagation 

Seeds are collected by hand July–August, placed in paper bags, and allowed 

to continue to dry inside in a dry room. Seeds are de-awned and cleaned 

using a Westrup machine with No. 14 screen, three times using a hard brush 

and a 3 by 5/16 screen on the clipper with 1⁄2 airflow. The number of Green 

Ridge seeds per kilogram was 485,950 at 9.9 percent moisture content. Seed 

viability by tetrazolium testing was 92 percent. Literature reports a maximum germination rate of 25 percent and optimum germination temperature 

of 15–25 oC (59–77 oF). The mean germination by in vitro germination 

testing of the study seeds using standard conditions was 64.8 percent. Seeds 

placed in a furrow and covered germinated and survived better than those 

broadcast seeded. Seeds sown in late September at Green Ridge did not 

begin to germinate until soil temperatures had warmed to 10 oC (50 oF).

Germination based on accumulated emergence was 32.8 percent; survival 

was 29.0 percent, and the following year, 13.4 percent. Trend in emergence 

and survival over the first growing season is shown in figure A14. In the 

second year, average leaf length was 7.1 cm. Achnatherum thurberianum

may extend the range of adaptation of the grasses as it appears adapted 

to more open, xeric habitats than the other grasses so might occupy drier 

microsites in the landscape. 

References

Archer (2000), Evans and Young (1978), Hitchcock (1951), Martens et al. 

(1994), USDA NRCS (2006). Young and Evans (1978).

ACTH7
78 GENERAL TECHNICAL REPORT PNW-GTR-823

Elymus elymoides (Raf.) Swezey

Bottlebrush squirrel tail 

Poaceae

ELEL5

Elymus elymoides is a short-lived perennial grass with culms 1–50 cm tall, 

leaf blades are flat to involute, 5–20 cm long and 1–3 mm wide with soft 

whitish pubescence. The inflorescence, a spike, erect 2–7 cm long with 

widely spreading awns 2–10 cm long. Fruit are caryopses.

Distribution and habitat 

Ranges from British Columbia to South Dakota, Missouri, Texas, California, 

and Mexico. Occurs in diverse dry habitat and ecotones of deserts, valleys, 

foothills, and mountain meadows at 610 to 3350 m (2,000 to 11,000 ft). 

Height varies with soil, moisture, and elevation. Early colonizer of disturbed 

sites but can be found in any of the successional stages. Cool-season species 

but tolerates full sun and drought. Can tolerate moderately saline or alkaline 

soils but grows poorly in granitic soils.

Reproductive ecology

Flowering occurs from late May through July. Species is wind pollinated but

also self-fertile. Undamaged root crown will regenerate but new plants depend on seed dispersal. Self-fertilized seeds mature from June to September.

The mean filled-seed rate of seeds collected from Green Ridge on the eastside central Oregon Cascade Range was 75.0 percent in 2004 and 81.8 

percent in 2005.

Propagation

Seed heads were determined to be dry by the spreading of the awns from 

the rachis, which occurs as the plant dries, as determined by color change 

from green to pale yellow. Seed heads broke off the stem easily if the plant 

had cured. The long awns made it difficult to place into paper bags, so 

greater care was needed to ensure they stayed in the bags for drying and 

storage. Larger bags are recommended than those used for seed-only collections. Seeds are de-awned and cleaned using a Westrup machine with No. 

14 screen twice through with hard brush. Screen with 1/18 by 1⁄4 screen on 

Clipper with 2/3 air. Or can air blow at 25 mm with 2 by 24 screen. Elymus ELEL5
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 79

elymoides can produce large numbers of highly germinable seeds. The number of Green Ridge seeds per kilogram was 190,440 at 9.7 percent moisture 

content. When conditions are right, germination is rapid and stratification 

is not necessary. The mean germination rate of unstratified seeds collected 

from Green Ridge was 81 percent. Germination has been reported highest 

at night/day temperatures of 10/20 oC, (50/68 oF) but is inhibited at 20/30 oC 

(68/86 oF). Study seeds sown in furrows covered with soil in late September 

at Green Ridge germinated before February the following year (probably 

late fall) confirming that no stratification is needed. Germination based on 

accumulated emergence at the Green Ridge site was 62.8 percent. Mean 

survival by late May was 46.2 percent, and by May the following year, 15.3 

percent. Trend in emergence and survival in the first year is shown in figure 

A15. Average herbceous cover of the subplot was 24 percent in May and 13 

percent the following year. Cover per surviving individual actually increased 

because of height growth and tillering of surviving plants. Average height by 

May the second year was 9.1 cm. Results were excellent in growing out grass 

seed at Lucky Peak Nursery, Boise, Idaho, with 0.3 lb seed producing 2.74 lb 

the first year after sowing and 21.8 lb the following year.

References

Beckstead et al. (1995), Hardegree et al. (2002), Harmond (1968), Hitchcock 

(1951), Jones (2006), O’Brien (1980), Rose et al. (1998), Simonin (2001), 

USDA NRCS (2006), USDI BLM (2003). 

ELEL5
80 GENERAL TECHNICAL REPORT PNW-GTR-823

Festuca idahoensis Elmer

Idaho fescue

Poaceae

FEID

Festuca idahoensis is a cool-season, densely tufted, long-lived, perennial 

bunchgrass; with leaf blades that are scabrous, filiform, and involuted. 

Culms range widely in height (30–100 cm) with narrow panicles and 5–7 

flowers in each spikelet with short awns (2–4 mm); fruit are caryopses. 

A typical bunchgrass with a caespitose growth form can reach 38 cm in 

diameter through clonal tillering. 

Distribution and habitat

The range of F. idahoensis extends from British Columbia and Alberta south 

to California and Colorado. It is found in mountainous terrain growing commonly in rocky and open forests or grasslands at 300–4000 m elevations. 

Festuca idahoensis is a constant plant community member and indicator of 

the Pinus ponderosa/Purshia tridentata/Festuca idahoensis association. It 

is well adapted to coarse sandy loam but also grows in well-drained, coarse 

soils consisting of rock and sand. The species grows in a variety of light 

conditions from full light to partial shade and is drought tolerant. 

Reproductive ecology

Although clonal spread through tillering is common, sexual reproduction 

through wind pollination is the primary mechanism for establishing new 

individuals. The species is long-lived and can persist as long as 60 years. 

Flowers are hermaphroditic and are wind pollinated. Sexual reproductive 

success can vary spatially and from year to year. The mean rate of filled 

seeds collected from Green Ridge on the east-side central Oregon Cascade 

Range was 47.0 percent in 2004 and 40.5 percent in 2005. Seeds mature in 

summer and disperse in July and August. In late summer, most of the seeds 

are dormant so that wetting by infrequent rainstorms will not cause them to 

germinate. However, seed germinates in late fall before the ground freezes 

and into late winter-early spring. FEID
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 81

Propagation 

Mature seeds are collected in mid summer. Mature flowering stems turn tan 

or light brown and lemmas separate or “fan out.” Seeds are easily collected 

by hand just before they shed. The mean percentage of filled seeds collected 

at Green Ridge was 47.0 in 2004 and 40.5 in 2005. Seeds are cleaned using 

a Westrup machine with No. 12 screen run twice then air blown at 22 mm. 

A medium brush and No. 40 screen can be used and run twice on a Westrup 

machine. Screen with 1/16 by 1/4 cross-slot screen on Clipper with 1/4 air. 

The number of seeds per kilogram was 676,050 at 9.2 percent moisture 

content. Seed viability using tetrazolium was 83 percent, and germination 

rate of unstratified seeds under standard test conditions was 80.8 percent. 

Study seeds were sown at Green Ridge 1–2 cm deep in furrows in late 

September. Seeds germinated before winter and emerged by February. 

Based on accumulated emergence in the spring, germination of sown seeds 

was 48.1 percent. Peak emergence was in February with some attrition over 

the following months. Survival was 30.5 percent by May, and the following 

May, 9.5 percent. Trend in emergence and survival of seedlings over the 

first growing season is shown in figure A16. Average cover in the subplots 

was 11.3 percent in 2005 and 11.4 percent in 2006, an increase relative to the 

number of surviving seedlings because of tillering. Average leaf length was 

8.3 cm by May of the second year. Results in growing out F. idahoensis for 

seed at Lucky Peak Nursery, Boise, Idaho, were good. About 0.08 lb of seed 

collected from Green Ridge produced 9.00 lb the second year after sowing.

References

Doescher et al. (1985), Goodwin et al. (1995,1996), Harmond (1968),

Hitchcock (1951), Johnson (1998), Liston et al. (2003), USDA NRCS (2006), 

USDI BLM (2003), Zouhar (2000). 

FEID
82 GENERAL TECHNICAL REPORT PNW-GTR-823

Poa secunda Presl.

Sandberg bluegrass

Poaceae

POSE 

Poa secunda is a short-lived, shallow-rooted, cool-season, perennial bunchgrass, part of a large complex of closely related grasses that differ ecologically and known collectively as Sandberg bluegrass. Culms erect, 30–50 cm, 

from a tuft of short, basal foliage. Blades short, soft, flat or folded. Panicle 

narrow, 2–10 cm long, spikelets spreading during anthesis 4–6 mm long, 

glumes acute, keeled; lemmas are without awns. Fruits are caryopses. 

Distribution and habitat 

Range is wide extending across western North America from Yukon south 

to southern California east to New Mexico and Nebraska. May be found in 

prairies, meadows, open forests, rocky slopes and mid to subalpine elevations growing in well-drained soils. Adapted to cold winters and dry, warm 

summers. 

Reproductive ecology

The species is relatively short-lived, reproduction by seed. Wind pollinated, 

but also self-pollinated. Poa secunda is also apomictic (produces fertile 

seeds without pollination). Flowers wind pollinated but reported to attract 

flies. Flowering occurs mid to late May and seeds mature July–August. Poa 

secunda is known to hybridize with P. pratensis and P. nervosa. The rate of 

fertile seeds may not be high. Mean filled-seed rate of seeds collected from 

Green Ridge on east-side of central Oregon Cascade Range was 35.0 percent 

in 2004 and 33.2 percent in 2005. 

Propagation

Poa secunda seeds are collected mid July–early August. Seeds are harvested 

by grasping the stem below the inflorescence and gently pulling upward, 

or by clipping the inflorescence. The mature seeds detach easily and are 

gathered in paper bags for transport to lab for further processing. Seeds 

are cleaned using a Westrup machine with medium brush and screen, hand 

screened with approximately 1/13 circular hand screen, and air blown, or POSE
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 83

screened with 1/13 round screen on Clipper and 1/4 air. The number of seeds 

collected from Green Ridge, Deschutes National Forest, per kilogram was 

1,655,800 at 8.8 percent moisture content; viability by tetrazolium testing 

was 69 percent. Seed germination in the lab without stratification at 10 oC 

with 10 h light was 51.6 percent as reported by Deering and Young (2006). 

Germination of seeds sown in late September at Green Ridge based on 

accumulated emergence was 46.3 percent; mean survival by late May was 

26.1 percent and by May the following year, 15.8 percent. Seeds germinated 

in late fall, and maximum germination had occurred by February. Note the 

trend in emergence and survival of seedlings during the first growing season 

shown in figure A17. Leaves grew slowly; median leaf length the second 

year was 3.7 cm. However, vegetative cover of the surviving seedlings 

increased from 1.0 to 5.7 percent because of tillering. Seeds collected from 

Green Ridge and sown at Lucky Peak Nursery, Boise, Idaho, resulted in 0.05 

lb of seeds yielding 8.50 lb in the second year after sowing and 4.46 lb the 

third year for a total increase > 25,000 percent. 

References

Darris (2007), Deering and Young (2006), Harmond (1968), Hitchcock 

(1951), Howard (1997), Rose et al. (1998), USDA NRCS (2006). 

POSE
84 GENERAL TECHNICAL REPORT PNW-GTR-823

Pseudoroegneria spicata (Pursh.) A. Love

Bluebunch wheatgrass

Poaceae

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Pseudoroegneria spicata is a long-lived, cool-season, perennial grass. The 

leaves are narrow, flat or rolled, and slightly bluish-green. Culms are highly 

tufted, erect, almost wiry and 60–100 cm in height. Spike (flower head) is 

slender and upright, made up of stalkless spikelets up to six-flowered, glumes 

narrow, with lemma tipped by twisted awns half as long as spikelet. 

Distribution and habitat 

Range is throughout western North America from Alaska south through

California and New Mexico, and from east of the Coast Range to Saskatchewan, Michigan, and Texas. Pseudoroegneria spicata ocurs in dry, open 

forest types, plains and prairies, on slopes, and open areas. The roots have a 

waxy covering that allows them to conserve moisture. May grow in full to 

partial sun; drought tolerant.

Reproductive ecology

Wind pollinated; however, seeds are highly self sterile; production of seeds 

and flowers does not occur every year. Propagates primarily by tillering but 

requires sexual reproduction for seed dispersal or repopulation after severe 

fire. Filled-seed percentages may vary from year to year. The mean rate of 

filled seeds from Green Ridge on the east side of the central Oregon Cascade 

Range was 33.3 percent in 2004 and 22.6 percent in 2005. This species’ 

populations may be under-represented because of low fecundity and might 

benefit from supplementary seeding.

Propagation

Seeds are not easily harvested because seeds rapidly shed and few are filled. 

Seeds are collected by hand when they appear ready to shed, indicated by 

awns at right angles to stem and culm no longer green. The culm is grasped 

just below the inflorescence, bent 90 degrees, and gently pulled so that ripe 

seeds release into a paper bag. Seeds were cleaned using a Westrup machine 

with screen No. 13 or with hard brush and screen No. 12. Filled and empty 

seeds and chaff were separated with air at 18 mm or screened with 1/18 by 

1/4 screen on Clipper and 2/3 air. Reported number of seeds per pound is PSSPS6
Evaluation of Native Plant Seeds and Seedings in the East-Side Central Cascades Ponderosa Pine Zone 85

140,000; the number of Green Ridge seeds per kilogram was 267,790 at a 

moisture content of 9.3. Viability was 87 percent. The mean germination rate 

of unstratified seeds under standard conditions was 75.2 percent with about 

10 percent moldy. 

Seeds collected and sown at Green Ridge in the fall appeared to have 

germinated before winter. Germination based on accumulated emergence 

was 41.6 percent. Survival was 25.8 percent by the end of May. The trend in 

emergence and survival of seedlings at Green Ridge through the first growing season is shown in figure A18. Survival in May the following year was 

6.4 percent; average leaf length of surviving seedlings was 10.0 cm. Cover 

in subplots decreased from 6.4 percent in 2005 to 4.1 percent but increased 

in proportion to the number of surviving seedlings because of height growth 

and tillering. In 2006, the plants had not yet produced culms. Pseudoroegnaria spicata usually reaches maturity in 2 to 3 years. Seeds collected from 

Green Ridge and sown at Lucky Peak Nursery, Boise, Idaho resulted in an 

excellent increase in seed with 0.25 lb of seeds yielding 3.50 lb in the second 

year and 0.81 lb in the third year for a total of 4.31 lb, an increase of > 1,500 

percent.

References

Hitchcock (1951), Ogle (2008), Rose et al. (1998), USDA FS (1937), USDA 

NRCS (2006), USDI BLM (2003), Zlatnik (1999).

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