A Field Guide to Biological 

Soil Crusts of Western U.S. 

Drylands

Common Lichens and Bryophytes

Roger Rosentreter

Matthew Bowker

Jayne Belnap

Photographs by

Stephen Sharnoff
2

Roger Rosentreter, Ph.D.

Bureau of Land Management

Idaho State Office

1387 S. Vinnell Way

Boise, ID 83709

Matthew Bowker, Ph.D.

Center for Environmental Science and Education

Northern Arizona University

Box 5694

Flagstaff, AZ 86011

Jayne Belnap, Ph.D.

U.S. Geological Survey

Southwest Biological Science Center

Canyonlands Research Station

2290 S. West Resource Blvd.

Moab, UT 84532

Design and layout by Tina M. Kister, U.S. Geological Survey, Canyonlands 

Research Station, 2290 S. West Resource Blvd., Moab, UT 84532

All photos, unless otherwise indicated, copyright © 2007 Stephen Sharnoff, Stephen Sharnoff Photography, 2709 10th St., Unit E, Berkeley, CA 94710-2608, 

www.sharnoffphotos.com/.

Rosentreter, R., M. Bowker, and J. Belnap. 2007. A Field Guide to Biological 

Soil Crusts of Western U.S. Drylands. U.S. Government Printing Office, Denver, 

Colorado.

Cover photos: Biological soil crust in Canyonlands National Park, Utah, courtesy of the U.S. Geological Survey. 
3

Table of Contents

Acknowledgements ....................................................................................... 4

How to use this guide .................................................................................... 4

Introduction ................................................................................................... 4

Crust composition ................................................................................... 4

Cyanobacteria .......................................................................................... 5

Successional series .................................................................................. 5

Ecological function ................................................................................. 6

Soils ......................................................................................................... 7

Lichen morphology ................................................................................. 7

Monitoring .............................................................................................. 8

Crust morphology .................................................................................... 9

Monitoring BSCs using level of darkness ............................................. 10

Moss Key .....................................................................................................11

Moss structure ....................................................................................... 13

Liverwort Key ............................................................................................. 25

Liverwort structure ................................................................................ 25

Lichen Keys ................................................................................................ 29

Major Division Key ............................................................................... 29

A: On Moss ........................................................................................... 30

B: Yellow ............................................................................................... 31

C: Black ................................................................................................. 31

D: Crustose ............................................................................................ 32

E: Fruticose ........................................................................................... 33

F: Foliose ............................................................................................... 34

G: Squamulose ...................................................................................... 35

Lichen structure ..................................................................................... 39

Lichen chemistry: spot tests .................................................................. 39

Appendix: Authorities ................................................................................. 92

Glossary ....................................................................................................... 94

Additional resources .................................................................................... 98

Websites ................................................................................................. 98

Books and articles ................................................................................. 99

Index .......................................................................................................... 101
4

Acknowledgements

Matt Bowker thanks Lloyd Stark for instilling an interest in bryophytes and 

ultimately biological soil crusts. Lloyd Stark and John Spence provided various assistance in moss identification. Technical assistance and advice were also provided 

by Bruce McCune, Stephen Sharnoff, Jeanne Ponzetti, Kara Thies, Patricia Vidiella, and Christy Parry. Graphics were created by Tina Kister. Some photos were 

provided by Michael Lüth, from Pictures of Bryophytes—Europe (www.milueth.de), 

and by David Miller (U.S. Geological Survey). 

How to use this guide

• This guide is primarily based on characteristics that can be observed in the field 

with the naked eye or a hand lens. Descriptions reflect ‘typical’ field appearance in North American drylands. The keys are constructed for dry material, 

while the full-page descriptions include colors when moist. Microscopic characteristics are included when they are necessary to aid in identification.

• Not all species in the keys have a full description. These species are treated 

under related species in the genus. When this is the case, the species name is 

followed by (ND), indicating it is not described on its own page.

• Distribution and elevation are indicated by areas shaded with yellow; when an 

entire area is yellow, this indicates that the species is present in all areas and/or 

at all elevations.

• Authorities are listed in the appendix for all species and synonyms.

• When a word or phrase is underlined in the description, that characteristic is 

critical in identification.

• Bold page numbers in the index indicate that a full description is included on 

that page for that species.

Introduction

Crust composition

Biological soil crusts (BSCs) are an intimate association between soil particles 

and cyanobacteria, algae, microfungi, lichens, and bryophytes (in different proportions) which live within or on top of the uppermost millimeters of soil. These 

communities have been known by a variety of names, including cryptobiotic, 

cryptogamic, and microbiotic soil crusts. They are found in all dryland regions 

of the world, including the polar regions, and in all vegetation types within these 

lands. In these landscapes, BSCs often cover all soil spaces not occupied by trees, 

grasses or shrubs and can comprise over 70% of the living ground cover. 
5

Cyanobacteria

The photosynthetic components of these crusts are 

dominated by cyanobacteria 

(formerly called blue-green 

algae), mosses, and lichens, 

with some green algae present 

as well. Cyanobacteria are 

one of the oldest known life 

forms. They were present in 

the oceans over 3 billion years 

ago and have existed on land for 

over 1 billion years. Cyanobacteria, particularly the large 

filamentous species, such as those in the genus Microcoleus, provide most of the 

cohesive quality of BSCs. In these species, many individual filaments are grouped 

together, surrounded by a sticky gelatinous sheath. These bundles of filaments 

wind throughout the uppermost soil layers, forming a net-like structure that binds 

together soil particles. This forms soil aggregates that create pathways for water 

infiltration and surfaces for nutrient transformations, while also increasing the 

soil’s resistance to wind and water erosion.

Successional series

Once the large filamentous cyanobacteria stabilize the soil, single-celled 

cyanobacteria appear. Species of Nostoc are very common, growing both within 

and on top of the soil. When in the soil, the single cells often form a long thread 

of hollow round balls, surrounded by a gelatinous sheath. Nostoc can also form 

sheets that lie loose on the soil 

surface. Wind and water shred 

these sheets into hair-like vagrant threads. Other cyanobacterial genera commonly found in 

BSCs include Schizothrix, Scytonema and Calothrix. Unlike 

the larger cyanobacteria, these 

smaller species are fairly immobile and stay on the soil surface 

where they can obtain sufficient 

light. However, the soil surface 

also receives high amounts of 

ultra-violet light which can harm 

Large, filamentous cyanobacteria, such as Microcoleus vaginatus, provide most of the cohesion 

that holds biological soil crusts together. Photo 

courtesy of USGS.

Single-celled cyanobacteria, such as the Nostoc 

commune pictured here, are common on soil that 

has been stabilized by large filamentous cyanobacteria. Photo courtesy of USGS.

s

s

t

g

r

B

t

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w

Single-celled cyanobacteria such as the Nostoc l
6

cellular structures. Thus, these 

smaller species contain high levels of UV-protective pigments, 

many of which are colored. 

Green algae (represented mainly 

by coccoid genera such as 

Chlorococcum, Macrochloris, 

and Stichococcus) can also be an 

important constituent of BSCs. 

Lichens and mosses colonize after the cyanobacteria. Unlike cyanobacteria, lichens and 

bryophytes have almost all of 

their photosynthetic tissue on or 

above the soil surface. Both phycolichens (lichens with green algal photobionts) 

and cyanolichens (lichens with cyanobacterial photobionts) occur in a range of 

growth forms, or morphological groups. Crustose and areolate lichens cover the 

soil with an appressed and more or less even layer of thalli (Buellia, p. 49-50 and

Trapeliopsis, p. 87-89). Squamulose lichens, such as Psora (p. 76-81) and Placidium (p. 73-74), have thalli divided into shield-, plate-, or scale-like squamules and 

thallus margins that are raised above the substrate. Foliose lichens are exemplified 

by species of Peltigera (p. 68). Fruticose lichens, which have cylindrical branches, 

are common in colder regions and are characterized by Aspicilia hispida (p. 46).

Most soil lichens have a layered, or stratified, thallus. However, some cyanolichens have unstratified gelatinous thalli (e.g., Collema, p. 55-56). Annual short 

mosses (< 0.5 cm high; e.g., Pterygoneurum ovatum in some habitats, p. 21) and 

tall perennial mosses (0.5 to several cm high; e.g., Syntrichia ruralis, p. 23) also 

occur in soil crust communities. Most perennial mosses are also classified as short 

mosses (e.g., Bryum argenteum, p. 14). Thalloid and leafy liverworts (p. 25-28) 

occur in BSCs as well.

Ecological function

The presence of these organisms on the soil surface increases soil stability. 

Because they are photosynthetic they also contribute carbon to the underlying 

soils. Free-living and lichenized cyanobacteria can also convert atmospheric 

nitrogen into bio-available nitrogen, and thus are an important source of this often 

limiting nutrient. All these organisms also secrete compounds that increase the 

bio-availability of phosphorus. Lichen morphological types with a more discontinuous cover (crustose, squamulose) allow water, gases, and seedlings to pass 

through to the soil surface, whereas mosses and lichens with a more continuous 

cover (foliose, fruticose) often block the flow of materials to the soil surface. 

Scytonema myochrous is another common cyanobacterium found in biological soil crust.

Photo courtesy of USGS.

-

y

n

- Scytonema myochrous is another common cy
7

Because BSC organisms are only metabolically active when wet, as the 

amount of precipitation increases, so does the level of BSC development and 

lichen and moss cover. However, BSC cover is restricted in areas where vascular 

plant cover is high because BSC organisms have a limited ability to grow upwards 

from the soil surface and cannot compete for light. Thus, the most conspicuous 

development of BSCs occurs in hot, cool, and cold drylands where plants are 

widely spaced.

Soils

BSCs are found on almost all soil types. Green algae are favored on more 

acidic and less salty soils, whereas cyanobacteria are favored on alkaline soils 

and soils with high salt content. Within a given climate zone, the cover of lichens 

and mosses generally increases with higher clay and silt content and lower sand 

content, as this also increases the stability and water-holding capacity of the soil. 

However, BSC cover and development is limited on clay soils with a high shrinkLichen morphology

Crustose (A, B) lichens form 

crusts that are so tightly attached 

to the substrate that they can’t be 

removed without damaging the 

lichen or the substrate. Crustose 

lichens can be continuous (A) or 

areolate (B), appearing tile- or 

island-like and divided into small 

areas by cracks. Gelatinous

(C) lichens have a single-celled 

structure of interwoven fungal 

threads with algae scattered 

between them and have a rubbery, 

jelly-like texture. Squamulose

(D) lichens have scale-like lobes 

that are usually small and overlapping. Foliose (E) lichens have 

lobes that are somewhat leaf-like 

and are relatively loosely attached 

to their substrates. Fruticose

(F) lichens are the most threedimensional, usually forming 

cylindrical branches that can 

grow upward.

a

i

a

(

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(

B

C

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A D

E

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8

swell coefficient. Habitats within a site that are more moist (e.g., under plant 

canopies and thin plant litter or on north/northeast exposures) generally support a 

greater cover of lichens and mosses. 

The external morphology of BSCs depends on climate, species composition, and disturbance regimes. The general appearance of BSCs can heavily 

influence ecosystem function by influencing how materials (e.g., water, seeds, 

plant litter, and nutrient-rich dust and soil) move across or are captured by the 

surface. Roughened surfaces slow material movement and increase the capture 

of resources, whereas a very smooth surface can have the opposite effect. Based 

on morphology, we define four categories of BSCs: smooth, rugose, pinnacled, 

and rolling. Smooth BSCs occur in hot deserts where soils do not freeze, and in 

recently disturbed areas. They are almost exclusively cyanobacteria, algae, and 

fungi. Chemical crusting is also common in this crust type. The other three BSC 

categories generally have lichens and mosses in addition to the cyanobacteria and 

fungi. Rugose BSCs have low surface roughness (< 3 cm) generally created by 

scattered lichen and/or moss clumps. Pinnacled and rolling BSCs are present only 

where frost-heaving occurs. Pinnacled crusts have up to 40% lichen-moss cover 

and can be up to 15 cm high. Rolling BSCs occur where high precipitation results 

in an extensive cover of lichens and moss, and the frost-heaving of these surfaces 

results in a gently rolling surface about 5 cm high. This classification is highly 

generalized, and all four categories are connected by intermediate crust types.

Monitoring 

There are multiple approaches to the monitoring of BSCs, depending on the 

monitoring goals. Areas dominated by cyanobacteria can be divided into categories based on the darkness of the soil surface (p. 10, Belnap et al. In press), as 

darkness is an indicator of cyanobacterial biomass and soil stability. The number 

of categories chosen depends on how easily the categories can be distinguished 

from one another and the level of resolution needed to meet monitoring goals. 

For lichens and mosses, it is best to record cover by species if sufficient expertise 

is available. When this is not possible, recording the morphological group (e.g., 

crustose/squamulose/foliose/fruticose lichens, short/tall mosses) is best, as this 

provides information on soil stability, seedling establishment, hydrology, and carbon fixation. It is also useful to record phycolichens and cyanolichens separately, 

as this gives information on nitrogen contributions. If recording by species or by 

morphological group is not possible, the next best option is recording cyanobacterial darkness, as well as the presence of lichens and mosses (lichens are easily 

distinguished from mosses: when wetted, mosses turn brown or green, whereas 

lichens do not change much in color). It is also useful to record the morphological 

type of BSCs being monitored.

For more detailed information, see Additional Resources on p. 98.
9

Smooth

Height: 0-1 cm

Rugose 

Height: 1-3 cm

Pinnacled

Height: 5-15 cm Height: 5 15 cm

Rolling

Height: 3-5 cm

Hyper-arid and disturbed deserts

Hot deserts

Cool deserts

Very cool deserts

Smooth biological soil crusts (BSCs) occur in hot hyper-arid deserts, such as the 

Colorado Desert, and in recently disturbed deserts. Rugose BSCs occur in slightly 

less arid deserts, such as the Mojave Desert. Pinnacled BSCs occur in mid-latitude 

cool deserts, such as the Colorado Plateau. Rolling BSCs are present only where 

frost-heaving occurs in winter, such as in the Great Basin. Photos courtesy of D.M. Miller 

and others, USGS.

Crust morphology
10

Biological soil crusts can be monitored using visually defined categories in areas 

dominated by cyanobacteria. These six categories were chosen for the Colorado Plateau (Belnap et al. In press). Tests showed these categories are easily distinguished 

by both trained and untrained observers and are closely related to cyanobacterial 

biomass and the resistance of the soil surface to wind and water erosion.

Photos courtesy of USGS.

Monitoring BSCs using level of darkness

Biological soil crusts can be monitored using visually defined categories in areas

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Moss Key

1a) Upper leaves or entire plant white or silvery due to lack of chlorophyll; plants 

usually small (0.5 mm tall) ........................................Bryum argenteum complex

1b) Plants not whitish or silvery; plant size various ................................................... 2

2a) Plants generally bearing long (up to 8 cm), conspicuous, curved sporophytes 

with pear-shaped capsules; most common in the Great Basin and Columbia 

Basin ............................................................................ Funaria hygrometrica

2b) Plants lacking long curved sporophytes .......................................................... 3

3a) Plants lacking awns or ending in a short awn; light green to black ........... 4

4a) Plants light green, large (> 1 mm common), with tongue-shaped 

leaves (may be contorted when dry) and an abrupt, short point at leaf 

tip ....................................................................................................... 5

5a) Almost always bearing straight erect sporophytes (~ 1-2.5 cm 

tall); older sporophytes exhibit cylindrical capsules topped with a 

characteristic white column ....................................Tortula inermis

5b) If sporophytes are present, shorter (< 1.5 cm); young sporophytes 

topped with characteristic dunce-cap-shaped calyptrae (~ 2-5 mm 

long) .................................................................Encalypta vulgaris

4b) Plants darker; smaller leaves broadest below middle, not ending in a 

short point .......................................................................................... 6

6a) When dry, dark green to black above and may be brownish below; 

tall (often > 3 mm) skinny plants with imbricate, approximately 

lance-shaped leaves; sporophytes rare ........... Didymodon vinealis

6b) Olive green above and reddish brown below when dry; shorter 

plants with linear lance-shaped leaves (sometimes contorted, 

sometimes ~ imbricate); if present, mature sporophytes red with 

downward-angled capsules ..........................Ceratodon purpureus

3b) Plants with long awns (usually whitish and toothed); colors various ........ 7

7a) White awns longer than plant height; often appearing as white fuzzy 

tufts (plant buried or inconspicuous) ................. Pterygoneurum spp.

(Proceed to 8 if sporophytes are present)

ND = Not described in this book
12

8a) Plants green (~ 1 mm high); due to short setae, the sporophyte 

capsules are immersed in leaves or barely sticking out; calyptrae 

split in two or more places ..........Pterygoneurum subsessile (ND)

8b) Setae longer; sporophytes usually long and protruding; calyptrae 

split in only one place, often the awn is the only visible part .........

 ..................................................................Pterygoneurum ovatum

7b)White or yellowish awns, length less than plant height; plants are 

generally above ground and easy to see .............................................. 9

9a) Plants yellowish green or golden (mostly < 1 mm tall); awn a yellowish extension of an acuminate leaf tip, wider at base ............ 10

10a) Plants yellowish green; rarely in dense cushions; in arid areas 

 .................................................................. Bryum kunzei (ND)

(See description of Bryum caespiticium)

10b) Plants golden yellow with a magenta-colored stem (when 

wet), frequently in dense cushions; prefers shrub canopies in 

higher elevation areas ..............................Bryum caespiticium

9b) Plants light green or darker (not yellow); awn white and approximately the same width along its entire length ............................. 11

11a) Plants light green or dark green; awn white, not toothed ..... 12

12a) Plants light green with long tongue-shaped leaves (often 

> 2 mm when wet); sporophytes common in spring (~ 

1.5 cm tall), with dunce-cap-shaped calyptrae ..................

............................................................Encalypta vulgaris

12b) Plants dark when dry, green when wet; leaves oval with 

unusually stout leaf mid-rib near leaf tip (when wet); 

sporophytes uncommon and lacking dunce-cap-shaped 

calyptrae ................................................Crossidium spp.

11b) Plants lime green to blackish; awns white and toothed, reddish or brownish at base; sporophytes usually absent .......... 13

13a) Plants lime green to dark green at top, reddish at base, 

tall (often > 3 mm); leaves slightly twisted around stem 

when dry, squarrose to recurved when wet; leaf mid-rib 

frequently red .......................................Syntrichia ruralis
13

13b) Plants dark green to blackish at top, brown at base, small 

to medium (usually < 3 mm tall); leaves patent, not 

twisted around stem when dry; leaf mid-rib never red .....

........................................................Syntrichia caninervis 

Moss structure

Operculum

Calyptra

Capsule

Seta

Leaf

Rhizoids

Costa

Sporophyte Gametophyte

Upright moss Feather moss

Sporophyte Gametophyte
14

Bryum argenteum

Common name: Silver-tipped moss

Synonyms: Bryum argentum There are over 90 additional synonyms.

Description: Plants upright, generally unbranched, 

silvery green to nearly white, especially in upper 

leaves. Stems bulb-shaped, 0.5 to about 1 mm tall but 

sometimes up to several mm. Leaves 0.5-1 mm long, 

imbricate wet and dry, may or may not end in a short point or short awn. Leaf midrib percurrent to long excurrent. Sporophytes rare. 

Habitat: In the open and in areas with partial shade on soils, rocks, walls, cracks in 

cement, tree bark, roof tiles, etc.

Comments: This species is a true generalist occurring from the hot deserts to polar 

regions, often in disturbed areas. It is a common associate of Syntrichia caninervis

and S. ruralis but could be reasonably expected to co-occur with any species treated 

in this book. Bryum is one of the world’s most distinctive groups of mosses due 

to its white or silver color. It co-occurs with the very closely related Anomobryum 

lanatum which has more pointed leaf tips but is difficult to distinguish in the field, 

even for specialists. The leaf mid-rib of A. lanatum extends into a short point. Some 

researchers consider A. lanatum to be a subspecies of B. argenteum. 

14

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Large photo courtesy of Michael Lüth

oint or short awn Leaf mid-
15

Bryum caespiticium

Common name: Dry calcareous bryum moss

Synonyms: Bryum arenicola, B. symblepharum. This 

species has 19 additional synonyms in the genus Bryum

Description: Plants upright, generally unbranched, 

dull yellowish leaves, green when dry, bright golden 

yellow when wet, forming dense tufts. Stems conspicuously bright red or magenta when wet, typically about 

0.5-1 mm tall in arid regions but may be considerably taller. Leaves patent when 

wet, about 1 mm long. Leaf mid-rib well defined, usually long-excurrent, forming 

a smooth or slightly toothed yellowish awn. Sporophytes rarely observed except in 

very wet years. Seta is curved and terminates in an inclined to pendulous capsule, 

variable in shape and size, with a short slender neck. 

Habitat: On various soils at middle to high elevations. Very common in cool deserts, confined to higher elevations in hot deserts.

Comments: This species is a common associate of Syntrichia ruralis and Ceratodon 

purpureus. Its yellowish color distinguishes it from most other aridland mosses. The 

small yellow Bryum common in hot deserts and the Colorado Plateau is B. kunzei, a 

former subspecies of B. caespiticium and still considered to be so by some experts. 

Bryum kunzei is also yellowish and awned but lacks a red stem, does not generally 

grow in dense tufts, does not have patent leaves when wet, and occupies drier regions.

0 5-1 mm tall in arid regions

15

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Large photo courtesy of Michael Lüth
16

Ceratodon purpureus

Common names: Fire moss, puzzling moss

Synonyms: Barbula saussuriana, B. validinervia, 

Ceratodon antarcticus, C. grossiretis, C. minutifolius, 

C. validus, Leskeela cuspidate, Meesia kenyae, Tortula 

saussuriana

Description: Plants upright, generally unbranched, olive 

green above and reddish below when dry, younger tissue 

green when wet, mostly about 0.5-2 mm tall (up to a few cm) when mature, forming 

dense cushions. Leaves imbricate or sometimes twisted (in larger specimens) when 

dry, standing erect-patent when wet, usually about 0.5-1 mm long, but may be longer 

than 2 mm in large specimens. Leaf mid-rib strong, sub-percurrent to excurrent but 

awns are never present. Sporophytes uncommon in deserts but common in wetter 

regions. Setae yellow to dark reddish, 1-2.5 cm long. At maturity, sporophytes are 

distinctive based upon red color and capsules angled downward 90° from the seta.

Habitat: At middle to high elevations, especially in burned areas. Occurs in hot 

deserts but is confined to mountains in those regions.

Comments: This species is a common associate of Bryum caespiticium and Syntrichia ruralis. Throughout its entire range it is an extremely variable species. In the 

drylands treated here, its combination of relatively short stature, dense cushions, 

drab green color, and lack of awn distinguishes it, while the characteristic red sporophyte with angled-downward 

capsule make it instantly recognizable.

cm) when mature forming

16

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Inset photo courtesy of Matt Bowker.
17

Crossidium spp.

Common name: Tassel moss

Synonyms: Crossidium aberrans: C. spatulaefolium; 

C. crassinerve: C. desertorum, C. erosum, Tortula 

crassinervia; C. squamiferum: Barbula squamifera, C. 

succulentum, T. squamifera

Description: Plants upright, generally unbranched, 

brownish green or grayish green when dry, usually very 

small and inconspicuous (~ 0.5-1 mm tall, but up to 1 cm in large specimens of C. 

squamiferum), often forming grayish crusts created by dark dot-like plants against 

a background of lighter soil. Leaves oval-shaped, imbricate and recurved when dry, 

erect to patent when wet, about 0.6-1.4 mm long (up to 2 mm in C. squamiferum). 

Leaf margins are colorless only in Crossidium squamiferum. Leaf mid-rib appears 

to be very thick under a hand lens, occupying over half the width of the leaf in some 

species. Leaf mid-rib is always excurrent, ending in a shiny colorless awn. Sporophytes uncommon except in wet years.

Habitat: On dry soils, in shady places or in the open. Common in warm deserts in 

general, especially abundant on gypsiferous soils (C. seriatum).

Comments: All Crossidium species share some growth of filaments on the inner leaf 

surface along the leaf mid-rib. Crossidium may be confused with Pterygoneurum

which never has a patent leaf stance, has a longer and clearly white 

awn, frequently fruits in the spring, and is swollen at the base. Pseodocrossidium crinitum, common in the Chihuahuan Desert, has more 

lance-shaped leaves which twist around the stem.

small and inconspicuous (~

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Didymodon vinealis

Common names: Screw moss, bearded moss

Synonyms: Barbula chrysochaete, B. constricta, B. 

elbertii, B. fusia, B. leuhmannii, B. pachydictyon, B. 

rectifolia, B. subcontorta, B. subtorquata, B. torquata, B. 

vinealis, Didymodon insularis, Tortula insulana

Description: Plants upright, often branched, nearly 

black above and brownish below when dry, upper tissue 

emerald green when wet, forming a dense cushion of slender plants up to about 2 

cm tall. Leaves lance-shaped, imbricate when dry, erect when wet, not twisted or 

crisped, 0.8-2.5 mm. Awn lacking. Leaf mid-rib percurrent or ending shortly below 

the apex. Sporophytes rare.

Habitat: On various soil types in variable climate conditions. In deserts it occurs in 

sites that are shaded in the winter by shrubs or rocks. May also be found on coastal 

dunes.

Comments: This species is highly variable—the characteristics described here refer 

to its typical appearance in desert and steppe regions. Its tall slender stems, relatively 

small leaves, dark color, lack of awn, and densely packed populations distinguishes 

it from most other mosses. Other rarer Didymodon species (D. trifarius, D. australasiae) tend to be smaller plants in more sparse populations. Syntrichia

species may be similarly colored but have a white awn. Grimmia

species are typically found on rock and occasionally on soils but most 

have at least sparse awns. 

nder plants up to about 2

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19

Encalypta vulgaris

Common name: Common candle snuffer moss

Synonyms: Bryum extinctorium, Encalypta australis, E. 

extinctoria, E. novae-seelandiae, E. orsinii, E. pumila, 

E. tasmanica, Hymenostoma encalyptroides, Tortula 

mairei

Description: Plants upright, generally unbranched except in unusually large specimens, upper younger tissue 

dull green when dry and light green when wet, brownish or reddish in the lower portion, usually 1-2 mm tall in arid regions but potentially several cm tall. Plants form 

loose cushions. Leaves very large (1-3 mm long) and tongue-shaped, widest above 

the center, strongly twisted when dry. Leaf mid-rib sub-percurrent or percurrent, 

ending in a short point or short, smooth, white awn. Sporophytes common. Setae 4-8 

mm, straight, yellowish red. Calyptrae 2-5 mm, dunce-cap-shaped. 

Habitat: Occasional in relatively mesic areas and microhabitats within dry areas.

Comments: The common name refers to the often observed large calyptrae. Encalypta vulgaris co-occurs and intergrades with E. rhaptocarpa which lacks awns, 

and these two can be difficult to tell apart. This species can be distinguished from 

Syntrichia ruralis by its shorter smoother awn, leaves which do not twist around 

the stem when dry, and frequent sporophytes with conical calyptrae. It may also 

resemble Tortula inermis which has taller (1-2 

cm) setae and cylindrical capsules with a white 

column on top.

dull green when dry and ligh

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Funaria hygrometrica

Common name: Cord moss

Synonym: None

Description: Plants upright, mostly short and unbranched, sometimes with 1-2(3) branches from the 

base, loosely tufted or scattered. Younger tissue bright 

green, becoming duller with age. Upper leaves may 

form an oval, round, or bud-like cluster, especially in 

young plants. Lower leaves much smaller. Leaves, in general, are ovate, obovate to 

oblong, sharply pointed to acuminate, and may be twisted when dry. Leaf mid-rib 

usually slender, ending below the leaf tip to shortly excurrent, but not forming an 

awn. Sporophytes common. Long (1-8 cm), conspicuous, curved setae terminate in 

a pear-shaped capsule (1.5-2 mm) with a distinct neck. Setae are curved when moist 

and strongly twisted when dry.

Habitat: On soils, often in disturbed or burned sites, occasionally in rock cracks. 

Present in all North American deserts, but only common in the Great Basin and 

Columbia Basin. Confined to more mesic areas in warmer deserts.

Comments: An early colonizer, this annual species is dispersed by spores. May 

be an early colonizer after fires, primarily in cooler deserts. Along with Ceratodon 

purpureus and Bryum argenteum, this is one of the most cosmopolitan mosses in the 

world and can be instantly recognized when 

the conspicuous sporophytes are present. 

neral are ovate obovate to

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Inset photo courtesy of Matt Bowker.
21

Pterygoneurum ovatum

Common names: Ovate pterygoneurum moss, onion 

moss

Synonyms: Barbula cavifolia, Gymnostonum pulvinatum, Pottia pilifera, Stegonia mouretii var. crinita

Description: Plants upright and unbranched, yellowish 

or brownish when dry, greening up somewhat when wet, 

minute and bulbous like miniature cabbages or onions. 

Plants may form dense hoary cushions or be scattered among other species. Stems 

often partially buried, up to 0.5 mm tall. Leaves erect or imbricate when dry, patent 

when moist, terminating in a very long (often > 3x the leaf length) white awn. Leaf 

mid-rib broad and strong. Sporophytes common in spring, long and protruding a few 

mm above the leaves. Calyptrae are split on one side. 

Habitat: On various soils, often on well-drained soils.

Comments: Pterygoneurum ovatum is by far the most common species of the genus 

and is frequently found in warm aridlands and infrequently found in cool aridlands. 

Pterygoneurum is possibly the most distinctive genus of aridlands because the 

overall appearance often resembles a whitish tuft of awns with plants nearly invisible. It is a common associate of Syntrichia caninervis. Determinations within the 

genus require sporophytes and microscopic observations. Pterygoneurum subsessile

is usually larger, has sporophytes with shorter setae scarcely protruding 

beyond the leaves, and calyptrae that split in 2 or more places. It may 

be very prevalent in disturbed areas. 

Plants may form dense hoar

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Syntrichia caninervis

Common name: Short twisted moss

Synonyms: Barbula caninervis, Tortula caninervis, T. 

desertorum, T. bistratosa

Description: Plants upright, simple or branched, nearly 

black above and brownish below when dry, younger 

tissue green when wet, forming loose cushions. Stems 

typically about 0.5-2 mm tall but potentially much larger. Leaves imbricate and not twisted when dry, standing erect to squarrose when wet, 

typically about 1.0-2.0 mm long. Leaf mid-rib stout, dark reddish brown, excurrent 

and terminating in a conspicuous, white, toothed awn. Sporophytes rare but might be 

found in mesic microhabitats, resembling those of Tortula inermis.

Habitat: On various soils at low to middle elevations. Often dominant in hot deserts 

and the Colorado Plateau but largely replaced by Syntrichia ruralis in the Great 

Basin and Columbia Basin. 

Comments: This species is frequently a dominant moss in drier warm deserts. It is 

a common associate of Bryum argenteum and B. kunzei. Its relatively large stature, 

white awn, and dark color easily distinguishes it. The closely related Syntrichia 

ruralis has leaves twisted around the stem when dry, is generally taller than 2 cm, 

is dull green above and reddish below when dry, and has a red leaf mid-rib. Under a 

microscope, the leaves of Syntrichia caninervis are two or more cells 

thick, in contrast to S. ruralis which 

are only one cell thick.

erect to squarrose when wet

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Syntrichia ruralis

Common name: Twisted moss

Synonyms: Barbula ruralis, Tortula longimucronata, T. 

ruralis

Description: Plants upright, simple or branched, dull 

green to almost black above and reddish below when 

dry, upper part of plants bright green when wet. Plants 

forming loose cushions. Stems typically about 2-20 mm 

tall, sometimes up to several cm. Leaves twisted around stem when dry, squarrose 

to recurved when wet. Leaf mid-rib clearly red, terminating in a conspicuous, white, 

toothed awn. Sporophytes are rare, resembling those of Tortula inermis when present.

Habitat: On various soils at middle to high elevations, often in partial shade. May 

be dominant in cool deserts, common in the Sonoran Desert, and confined to mountainous regions in the Mojave Desert.

Comments: This species is a common associate of Ceratodon purpureus and Bryum 

caespiticium. It is among the tallest of biological soil crust mosses and, as such, 

likely plays distinct functional roles regarding hydrology and germination of vascular plant seeds. This, together with its twisted leaves and white awn, distinguishes it. 

Polytrichum species have rigid straight leaves which do not twist around the stem. 

The closely related Syntrichia caninervis is smaller, darker, thicker, 

and is generally shorter than 2 mm. Syntrichia princeps usually bears 

abundant sporophytes.

tall sometimes up to several

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Tortula inermis

Common name: Hairless twisted moss

Synonym: Syntrichia inermis

Description: Plants upright, simple or branched, dull 

green, sometimes reddish in lower portions when dry, 

bright green when wet, forming loose cushions. Stems 

typically 0.5-1.5 mm tall. Leaves spiraling at the tips 

when dry and erect to patent when wet. Leaf mid-rib 

may be reddish and terminates in a short point or very short awn. Sporophytes common, reddish brown or darker at maturity, usually 1-2.5 cm tall. Capsules erect and 

cylindrical, when open bearing distinctive, white, columnar peristomes at the tip.

Habitat: At low to medium elevations in protected areas, particularly in the hot 

deserts.

Comments: This species is frequently observed in the partial shade afforded by 

rocks in the Mojave and other warm deserts. When wet, it may superficially resemble Encalypta species, but this taxon tends to occupy higher elevations and has a 

shorter sporophyte with a bright 

red seta and large, distinctive, 

conical calyptra. The sporophyte 

can resemble those of closely related Syntrichia species, but Syntrichia

is darker and has 

long toothed awns. 

This is one of the 

most common and 

widespread mosses 

in the warm deserts 

of North America.

ort awn Sporophytes com

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Liverwort Key

1a) Thallus leafy; a flattened, green, slender, leaf-like structure ................................ 2

1b) Thallus thalloid; a minutely thread-like black structure with a series of minute 

leaves ..............................................................................Cephaloziella divaricata

2a) Grayish green leafy thallus with a fringed purple margin .. Athalamia hyalina

2b) Green leafy thallus with an entire green margin ....... Fossombronia longiseta

Liverwort structure

Thalloid liverwort

Leafy liverwort

Rhizoids

Leaf

Underleaf

Lobe

Lobule

Perianth

Capsule

Seta

Sporophyte Gametophyte

Rhizoids

Perianth

Capsule

Seta

Gemmae cup

Thallus

Gametophyte Sporophyte
26

Athalamia hyalina

Common names: Athalamia, thalloid liverwort 

Synonyms: Clevea hyalina, Plagiochasma erythrospermum

Description: Plants thalloid, dioecious, grayish green,

often tinged purplish at the margins, becoming blackish with age. Thalli small and fairly narrow (2.5-5.5 

mm wide × 0.5-1.5 cm long), in irregular mats 4-7 cm 

across, not aromatic, delicate. Upper surface broadly and shallowly u-shaped or 

v-shaped in section, often disintegrating with age. Lower surface green or reddish. 

Rhizoids colorless. Sporophytes originating on the dorsal side of the thallus and not 

in the apical notch.

Habitat: Damp and slow-to-dry soils around rocks and at the margins of drainages and steep hillsides. Also infrequent in clay loams and silt loams in areas with 

ephemeral saturation. Can occur in or on the margin of vernal pools or on the edges 

of ponds. This species can occur in any arid habitat in the Great Basin Desert.

Comments: Vegetative plants can be distinguished by the combination of conspicuous, colorless or purplish, ventral scale appendages that usually extend beyond the 

thallus apex and lateral margin, and pores of air chambers surrounded by a single 

circle of cells. The entire thallus will close like a book when it dries up, making it 

difficult to see. More widespread than reports would suggest, A. hyalina is most obvious on moist spring days. Riccia species look similar 

but have smaller thalli and lack purplish margins.

shallowly u-shaped or

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Cephaloziella divaricata

Common name: Common threadwort

Synonyms: Cephaloziella starkei, C. confervoides, C. 

byssacea

Description: Plants leafy, dioecious, black. Stems 

densely massed and thread-like, 3-10 mm long. Leaves 

numerous and distinct on both sterile and fertile stems, 

crowded near the shoot tips and deeply divided into 

two segments, about 2 mm long. Leaf lobes abundant, 2-celled. Gemmae reddish or 

purplish. Underleaves are narrow and undivided. Rhizoids can be numerous along 

the lower surface. Sporophytes rare. Perianth mouth almost uniformly purplish.

Habitat: Occasionally occurs with lichens on burned stumps as a pioneer species. 

Comments: This species can be confused with Cephaloziella rubella—especially 

in sterile forms—but C. divaricata is distinguished by its wide leaf lobes (6-10 cells 

wide at the base) and small but distinct underleaves, in contrast to the monoecious 

C. rubella which has narrow leaf lobes (3-5 cells wide at the base) and no underleaves. Also, the perianths of C. divaricata are distinctly cigar-shaped, and the lower 

parts of the perianths are frequently purplish (colorless in the upper part), as indicated by MacVicar (1926). However, in C. rubella, the perianths are oblong and the 

upper parts of the perianths are purplish. In aridlands it is most abundant in pristine 

and old growth habitats, while it can be an early successional species in 

moist habitats.

two segments about 2 mm l

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28

Fossombronia longiseta

Common name: Annual leafy liverwort

Synonyms: Androcryphia longiseta, Fossombronia 

kashyapii, F. vermiculata

Description: Plants monoecious, leafy, green with 

crimson on the uppermost leaf margins and rhizoids 

only, forming irregular patches on damp sandy soils. 

Leaves deeply cut on both sides of a stem-like mid-rib 

into ruffed leaf-like lobes. Shoots up to about 5 mm long × 1 mm wide × 0.5-1.0 

mm high. Rhizoids sometimes both crimson and colorless mixed on the same stem. 

Search for capsules at the apices of nearly fully elongated setae. Sporophytes clubshaped on a short stalk. Mature spores with ridges, 40-53 mm diameter. 

Habitat: Open, sunny sites, often with recent but light disturbance of the soil surface. Generally on clay, silty and gravelly soils of hillsides, road banks, paths, and at 

the base of rock outcrops. Mixed with bunchgrass in warm grasslands.

Comments: Vegetative plants can exhibit great morphological variation on the same 

shoot during a single growing season, depending on moisture, sunlight, and maturity 

level. Fossombronia longiseta has spores with 30 or more lamellae, or spines, as 

seen in equatorial optical section with a compound microscope. In side view, spores 

have closely spaced lamellae 1.5-3.5 μm apart. Spores in capsules before setae 

elongation often have shorter lamellae and spine heights than spores in 

capsules with elongated setae.

× 1 mm wide × 0 5 1 0

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29

Lichen Keys

Nomenclature follows Esslinger and Egan (1995) with a few exceptions. Lichens 

that commonly occur on soils as biological soil crusts are treated here. Lichens that 

normally occur on rock and occasionally or rarely occur on soils are not treated.

Major Division Key

1a) Thallus limited to growing on moss or organic debris ................ On Moss-Key A

1b) Thallus on various substrates ................................................................................2

2a) Thallus yellow, yellow-green (fluorescent) or orange ................Yellow-Key B

2b) Thallus other colors .........................................................................................3

3a) Thallus blackish or brownish black; the foliose and fruticose species are 

gelatinous when wet; thallus non-stratified ...........................Black-Key C

3b) Thallus another color or not apparent, the foliose and fruticose species 

not gelatinous when wet, thallus stratified ................................................4

4a) Thallus continuous or seemingly absent, crustose, with or without 

marginal lobes ...........................................................Crustose-Key D

4b) Thallus of discrete lobes, not crustose except for some lobate-margined crustose species ........................................................................5

5a) Thallus fruticose or 3-dimensional foliose .........Fruticose-Key E

5b) Thallus otherwise ..........................................................................6

6a) Thallus foliose .....................................................Foliose-Key F 

6b) Thallus squamulose, of discrete scale-like thalli, occurring in 

clusters ......................................................Squamulose-Key G
30

A: On Moss

Thallus growing on moss or organic debris.

1a) Thallus narrow foliose, green to brownish with age; lobe margins often frosted 

with pruina; rhizines present, with many lateral branches; common growing over 

mosses in moist microhabitats ............................................Physconia muscigena

(See Physconia perisidiosa if sorediate)

1b) Thallus not foliose ................................................................................................2

2a) Thallus commonly with apothecia ..................................................................3

3a) Thallus thick, generally white to cream or green (spores 1-celled) ...........4

4a) Disks black; thallus thick, gray-green to whitish; apothecia sunken 

within the thallus .............................................. Megaspora verrucosa

4b) Disks yellowish; thallus thick and warty, pure white to cream-colored; apothecia sessile; commonly growing over Selaginella (spike 

mosses) or detritus ........................................ Ochrolechia upsaliensis

3b) Thallus thin to unevenly thick with thin areas (spores 2-celled, dark) ......5

5a) Thallus thin to very thin, generally dirty-gray; apothecia small (< 

1 mm); disks black with a well-defined rim, at least when young 

(spores small, 11-16 × 6-8 μm) ................................ Buellia punctata 

5b) Thallus thin to moderately thick, uneven in thickness (papillate); 

apothecia can be larger with age, often greater than 1 mm (spores 

larger, 18-24 × 8-10 μm) .................................Buellia papillata (ND)

2b) Thallus mostly lacking apothecia or apothecia lacking a margin and not 

round in outline ...............................................................................................6

6a) Thallus thick, gray to olive green; medulla C-, K+ red; surface warty with 

isidioid bumps and occasionally some soredia; common on moss clumps 

that grow on rock (Grimmia spp.) or on organic detritus; common in dry 

steppe habitats ............................................................Aspicilia mastrucata

6b) Thallus thin to granular with warty sections, greenish gray, olive-brown 

or brownish, C+ pink (fleeting), K-; soredia granular or powdery, whitish 

to yellow-brown in color; apothecia occasional, eccentrically shaped in 

outline, more flexuose (wavy) and variable in color from pale pinkish to 

dark brown, without a margin ................................Trapeliopsis granulosa

ND = Not described in this book
31

B: Yellow

Thallus on various substrates and yellow, yellow-green (fluorescent), or orange.

1a) Thallus light green or fluorescent greenish yellow to dull chartreuse ..................2

2a) Thallus squamulose to continuous areolate; apothecia red-brown or black 

with a lecanorine margin; occasionally parasitic on Diploschistes but often 

free-living (spores colorless, 1-celled, < 1 μm) ..........Acarospora schleicheri

2b) Thallus squamulose, scales dispersed to crowded, not at all a continuous 

areolate thallus; cortex UV+ dull orange; apothecia lacks a margin ................

....................................................................................................Psora icterica

1b) Thallus pale yellow, egg-yolk yellow, orange, or red-orange ..............................3

3a) Thallus egg-yolk yellow or pale dull yellow ...................................................4

4a) Thallus continuous crustose to subfoliose, forming lobes adnate to the soil, 

yellow; small marginal lobes often present ................................................5

5a) Thallus subfoliose with obvious lobate margins (spores 2-celled) ......

 ................................................................Fulgensia desertorum (ND)

5b) Thallus crustose, less foliose, and less lobed (spores 1-celled) ...........

 .............................................................................Fulgensia bracteata

4b) Thallus granular, not continuous, egg-yolk yellow; marginal lobes absent .

 ....................................................................................Candelariella citrina

3b) Thallus whitish, pinkish orange, yellow orange, or red-orange ......................6

6a) Thallus squamulose, white to pinkish orange to brick red, with upturned 

paler margins; soredia lacking; often on calcareous soils ..Psora decipiens

6b) Thallus more crustose, bright orange to yellow orange; soredia present; 

on slightly calcareous soils ............................................ Caloplaca tominii

C: Black

Thallus on various substrates, blackish to brown, greenish, or even gray; the foliose 

and fruticose species are gelatinous when wet, non-stratified.

1a) Thallus a thin black to dark brown crust of isidia or coarsely granular; apothecia rare, but if present are black with a black rim; photobiont green—scratched 

surface is a light green color (spores 1-celled) ...........................Placynthiella spp.
32

1b) Thallus foliose (sometimes minutely so); photobiont blue-green when surface is 

scratched ...............................................................................................................2

2a) Lobe margins with tiny white hairs; fairly common, often on soils and 

mosses .................................................................. Leptochidium albociliatum

2b) Lobe margins lacking tiny white hairs ............................................................3

3a) Thallus dull and smooth or coarsely wrinkled under a hand lens, lacking a 

cortex; margins of lobes swollen or nodulose (with minute lumps) but not 

fringed; often with abundant isidia ............................................................4

4a) Thallus small (< 2.5(3) cm diameter), foliose to subfoliose, weakly 

lobed if at all, often with isidia; apothecia often lacking (spores 

2-celled) ..........................................................Collema coccophorum 

4b) Thallus larger (1-6 cm diameter), foliose or lobate; isidia lacking to 

abundant; apothecia infrequent (spores 4-celled); widespread ............

 ......................................................................................Collema tenax

3b) Thallus brownish black, slightly shiny and finely wrinkled under hand 

lens, with a cortex; lobes erect, margins of lobes finely fringed; isidia 

occasionally marginal; often in more mesic sites .. Leptogium lichenoides

D: Crustose

Thallus on various substrates, continuous or seemingly absent, crustose with or 

without marginal lobes, not black or dark brown.

1a) Continuous crust, margins non-lobate ..................................................................2

2a) Thallus wholly sorediate, white, gray, or greenish ...................... Lepraria spp.

2b) Thallus lacking soredia, various colors ...........................................................3

3a) Thallus with tiny embedded to immersed or sessile perithecia and greater 

than 0.2 mm diameter; appearing as discolored dirt growing on mineral 

soils .........................................................................Thrombium epigaeum

3b) Thallus with larger apothecia present ........................................................4

4a) Thallus whitish to pale grayish, thin; colonies small (generally < 3 

cm); apothecial disks blackish to olive-green, sometimes with yellowish or greenish tinge; rare and inconspicuous, most often found 

on decaying organic matter infused with soil as well as on old rabbit 

dung or on mineral soils ........................... Texosporium sancti-jacobi 
33

4b) Thallus dirty cream or gray, usually thick; colonies can be large 

(2-12 cm); apothecial disks all black around the edges and sunken 

like a crater; very common on soils or growing over Cladonia spp. 

(spores becoming brown, many-celled, large) ...................................5

5a) Thallus thick with entire to smooth texture (spores 4 per ascus) ....

 .................................................................Diploschistes muscorum

5b) Thallus very thick, upper surface white and chalky (spores 4-8 

per ascus) ..................................................Diploschistes diacapsis

1b) Crusts with lobate margins ...................................................................................6

6a) Thallus thin, white, continuous, strongly adherent to the soil; apothecia 

black; often on calcareous, silty soils ..................................... Buellia elegans 

6b) Thallus thick, uneven in thickness or nodular, white (occasionally brownish), 

strongly pruinose, areolate; apothecia brown or reddish brown to blackish; 

on calcareous soils and gypsum soils .....Acarospora nodulosa var. nodulosa

E: Fruticose

Thallus on various substrates and with discrete lobes, fruticose or 3-dimensional 

foliose.

1a) Thallus of two parts: basal squamules and erect, hollow stalks (podetia) ............2

2a) Podetia cup-shaped with tiny (generally < 1 mm) squamules inside (10x hand 

lens), frequently poor or lacking, sometimes appearing as a colony of scales; 

very common in dry habitats, especially in calcareous areas ...........................

............................................................................................ Cladonia pocillum

2b) Podetia cup-shaped with soredia inside the cups ...............Cladonia fimbriata

1b) Thallus of one part, podetia rare, reduced, or lacking ..........................................3

3a) Lobes round in cross-section, not dorsiventral, olive, greenish, pale greenish, 

or tan to brownish; spores borne in apothecia but plants are usually sterile; 

rhizines lacking ...............................................................................................4

4a) Thallus free from the soil; branches dichotomous, short, thick, blunt; on 

calcareous soils ..........................................................................................5

5a) Thallus tipped with pale spots (pseudocyphellae) ................................

 ............................................................................ Aspicilia fruticulosa

5b) Apothecia and pseudocyphellae lacking ....................Aspicilia aspera

4b) Thallus at least partially attached to the soil ..............................................6
34

6a) Thallus erect, basally attached; branches terete with laminal pseudocyphellae .................................................................. Aspicilia hispida

6b) Thallus more or less of compressed mats, attached at several points 

along the lobes; lacking pseudocyphellae .......................................... 7

7a) Thallus fruticose, branching in sections resembling beads on a 

string, with obvious lobes; on soils or organic matter ..................8

8a) Thallus predominantly narrow, elongate and stringy; margins 

well defined, discrete; lobe tips sharply pointed and distinct 

from the main thallus, often black with forked tips, thallus Kor weakly K+ .............................................. Aspicilia filiformis

8b) Thallus more areolate and attached to the soil with only occasional stringy sections (resembling beads on a string); thallus 

margins poorly defined, diffuse; lobe tips similar in color and 

texture to main thallus, thallus K- .................Aspicilia reptans

7b) Thallus crustose to areolate, with flat, discrete, areolate to somewhat convex lobes; on soils and rock ..............................................

 .............................................. Aspicilia desertorum form terrestris 

3b) Lobes flattened in cross-section, dorsiventral, with margins strongly curled 

inward almost forming tubes, pale greenish to yellow-green; rhizines present 

...........................................................................Xanthoparmelia chlorochroa

F: Foliose

Thallus on various substrates, with discrete lobes, foliose or distinctly lobate crustose.

1a) Thallus sorediate, soredia terminal .....................................Physconia perisidiosa

(If soredia are marginal, Physconia enteroxantha (ND)

1b) Thallus not sorediate .............................................................................................2

2a) Lobes greater than 2 mm wide, thallus greenish to gray .................................3

3a) Lower surface with veins densely covered with dark brown hedgerows of 

rhizines ......................................................................... Peltigera rufescens

3b) Lacking veins on the lower side; thallus white.................. Buellia elegans

(Or see Acarospora nodulosa var. nodulosa in Key D: Crustose)

2b) Lobes greater than 2 mm wide; thallus brown ...............Massalongia carnosa
35

G: Squamulose

Thallus on various substrates, of discrete scale-like squamules, occurring in clusters.

1a) Squamules pale greenish, gray-green, greenish black, or bluish black ...............2

2a) Squamules sulfur green to greenish yellow ...............................Psora icterica

2b) Squamules whitish-gray to green or brown-green, not sulfur-green to greenish yellow ........................................................................................................3

3a) Squamules pale greenish, the edges free and usually upturned when dry, 

showing the whitish underside; apothecia borne on upright stalks ..............

 ................................................................................................Cladonia spp. 

(See Key E: Fruticose) 

3b) Squamules pale greenish or yellowish tinged, appressed, although the 

edges are often distinct; apothecia tan, more or less sunken in the thallus 

when young, becoming raised with time .................Squamarina lentigera

1b) Squamules some shade of white, gray, tan, brown, or blackish brown ................4

4a) Soredia present, similar in color to the thallus; thallus light gray; squamules 

small, appressed to ascendant, roundish to more or less elongate ....................

........................................................................................ Trapeliopsis steppica

4b) Soredia absent .................................................................................................5

5a) Perithecia present, immersed in the thallus, but ostioles are visible with a 

hand lens (10x) as small dark spots ...........................................................6

6a) Squamules often greater than 1.5 mm diameter, adnate, with conspicuous perithecia that have openings showing on surface of the 

thallus as slightly raised, larger, blackened spots (spores many-celled, 

brown) ..............................................................Endocarpon pusillum

6b) Openings of perithecia relatively subtle in surface view, appearing as 

minute dark spots or essentially invisible without a hand lens (spores 

1-celled, colorless) ............................................................................. 7

7a) Squamules with rhizines in a pale bundle .......................................

 ...................................................................Placidium lacinulatum

7b) Squamules lacking root-like rhizines ............................................8 

8a) Squamules with prominent, protruding, marginal pycnidia .......

 ....................................................... Placidium lachneum (ND)

8b) Squamules with laminal pycnidia .....Placidium squamulosum
36

5b) Apothecia present ......................................................................................9

9a) Squamules with distinctly pale edges, either because the edges are 

more pruinose than the centers or because the edges are upturned, 

exposing the pale lower surface .......................................................10

10a) Squamules pinkish orange to brick red, on calcareous soils .........

 .............................................................................Psora decipiens

10b) Squamules very dimple-shaped with a depression in the middle .

 ................................................................................Psora crenata

10c) Squamules some shade of brown or gray/pruinose over a brown 

thallus ........................................................................................ 11

11a) Thallus large (squamules up to 10 mm wide); edges of 

squamules upturned, exposing the pale lower surface; usually 

associated with soils or mosses over rock or rock crevices ......

 ...............................................................Psora nipponica (ND)

11b) Edges of squamules pruinose, upturned or flat ....................12

12a) Thallus light to dark brown; apothecia reddish brown; 

common on exposed, calcareous soils ..............................

............................................................ Psora tuckermanii 

12b) Thallus dark brown, whitish, or greenish tan; apothecia 

black .............................................................................13

13a) Apothecia marginal; on calcareous soils; ranging in 

color from chalky white (thickly pruinose) on highly 

calcareous substrates to a pale or greenish tan on 

more acidic substrates ...............Psora cerebriformis

13b) Apothecia laminal; squamules dark brown; edges 

raised, usually white/pruinose; uncommon, mainly 

in crevices in calcareous rock ....................................

 ........................................... Psora himalayana (ND)

9b) Squamules not pale-edged ...............................................................14 

14a) Squamules gray without an olive tinge; thallus C+ red, KC+ red; 

mainly west of the Cascade Mountains, common in California ..

 ............................................................Trapeliopsis glaucopholis 

14b) Squamules gray, cream, olive, blue, or greenish black, with or 

without white pruina; thallus C-, KC-; widespread .................15
37

15a) Squamules blue, olive, or greenish black, with or without 

pruina; thallus C- .................................................................16

16a) Squamules greenish black, epruinose; apothecia jet 

black; fairly common on soils and mosses ....................... 

.............................................................. Toninia ruginosa 

16b) Squamules dark olive, blue, or grayish olive, whitish 

with dense pruina; apothecia dusty black; almost always 

present on highly calcareous exposed soils at all elevations.......................................................Toninia sedifolia

15b) Squamules gray, cream, olive or greenish black; with or without white pruina; thallus KC+ or KC- ................................. 17

17a) Apothecia deep red to reddish brown (cut through apothecia to check the color) .................................................18

18a) Apothecia initially immersed but becoming sessile, 

never occupying the whole squamule ........................

 .................................................... Psora tuckermanii

18b) Apothecia persistently immersed in squamules and 

eventually expanding to occupy most of the squamule; photobiont blue-green (cyanobacteria) ..........19 

19a) Squamules 1-3(5) mm diameter, brown to 

black; upper surface without a cortex; uncommon on soils but more common east of the 

Continental Divide ......................Heppia lutosa

19b) Larger squamules (> 3 mm), occuring in colonies and lacking an upper cortex (not gray) .......

 ...............................................Peltula richardsii

19c) Squamules up to 8 mm diameter, brownish or 

olive to cream pruinose; upper surface with a 

cortex 8-50 μm thick . Heppia conchiloba (ND)

17b) Apothecia dark brown to black .....................................20

20a) Squamules with felty black rhizines (use hand 

lens), small, mostly about 1 mm or less, brown or 

grayish pruinose, appressed, the edges not upturned; 

medulla orange or yellowish orange .........................

 ....................................Phaeorrhiza sareptana (ND)

(See Phaeorrhiza nimbosa)
38

20b) Thallus yellowish brown with a white medulla, 

occurring more frequently in alpine and subalpine 

habitats .................................. Phaeorrhiza nimbosa

20c) Squamules mostly greater than 1 mm, brown 

to blackish brown or grayish to white pruinose, 

appressed or with edges free ................................. 21

21a) Apothecia persistently marginal or between 

the squamules; thallus pale brownish, whitish 

pruinose, or dark brown; squamules developing 

a cracked upper surface or becoming thickly 

white pruinose; apothecia concolorous with 

the thallus, initially with a differentiated rim, 

though often losing it soon in development, flat 

to convex, round in outline, marginal; surface 

of apothecia K+ red, best seen with compound 

microscope; on calcareous sites forming whitish brain-like mounds (spores 1-celled) .............

 .......................................... Psora cerebriformis

21b) Apothecia laminal, thallus brown to dark 

brown .............................................................22

22a) Squamules relatively small, usually 0.5-2 

mm broad; upper surface smooth or with 

weak fissures; cortex KC+ red or KC- .......

 ...........................................Psora montana

22b) Squamules often greater than 2 mm broad; 

upper surface with prominent fissures (use 

hand lens); cortex always KC- ...................

 .................................Psora globifera (ND)

(See Psora montana)
39

Certain chemicals react with 

lichen substances which are 

compounds (such as fatty acids) 

that occur in different locations 

on different lichens. “Medulla 

K+ yellow” means that if you 

moisten the medulla with K 

(potassium hydroxide), it will 

turn yellow. K/I indicates that 

first potassium hydroxide is 

applied, and then iodine.

Lichen structure

Lichen chemistry: spot tests

Chemicals used for lichen spot tests:

Symbol Compound

C Calcium hypochlorite

I Iodine

KI Potassium iodide

K Potassium hydroxide

N Nitric acid

P Para-phenylenediamine

UV Longwave ultraviolet light

Foliose lichen

Rhizines

Isidia

Soredia

Apothecia

Cyphellae

Stratified lichen

Rhizines

Medulla

Algae or

cyanobacteria

Upper cortex

Fungal hyphae

Lower cortex

Gelatinous lichen

Note: gelatinous lichens may 

or may not have an upper 

and lower cortex
40

Acarospora nodulosa var. nodulosa

Common name: Nodule cracked lichen

Synonym: Acarospora nodulosa var. reagens

Description: Thallus squamulose/areolate, appearing 

white due to dense pruina, growing in a continuous 

colony. Lower surface tan to pale brown. Squamules 

lobate. Rhizines lacking. Apothecia common, round to 

irregular, 1-2(3) per squamule. Disks brown, reddish 

brown to nearly black, smooth to cracked. Spores small, 

more than 60 per ascus. Photobiont green (Trebouxia).

Habitat: Common to abundant on gypsiferous and calcareous soils.

Chemistry: Cortex C-, K- (usnic acid only).

Comments: Acarospora nodulosa var. nodulosa occurs exclusively on gypsiferous 

soils. It co-occurs with other gypsophiles such as Psora decipiens and Fulgensia 

bracteata, along with a very diverse assemblage of mosses and other lichens. It 

could be confused with other large white lichens with dark apothecia, such as Psora 

cerebriformis, Diploschistes diacapsis, and Lecanora gypsicola. Acarospora nodulosa var. nodulosa is clearly squamulose with lobate squamules and large, flat, immersed, brown-black apothecia. Psora cerebriformis has a brain-like, hemispherical 

thallus and small, convex, black apothecia. Diploschistes diacapsis is 

a thick, crustose lichen with numerous crater-like, dark gray apothecia. 

Lecanora gypsicola has a chinky, crustose thallus, and only 8 large 

spores per ascus.

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p p
41

Acarospora schleicheri

Common names: Schleicher’s cracked lichen, soil paint 

lichen

Synonym: None

Description: Thallus squamulose/areolate, pale to bright 

sulfur yellow to green, often lobed at the margins, sometimes whitish pruinose. Rhizines lacking. Apothecia redbrown, large, usually immersed in the thalli with round 

to irregular disks but occasionally somewhat prominent with lecanorine margins, 

with a roughened appearance. Spores dozens to hundreds per ascus, single-celled, 

colorless, ellipsoid to spherical. Photobiont green (Trebouxia).

Habitat: On soils, often found growing in close association with Diploschistes

muscorum or D. scuposus. Acarospora occasionally grows on Diploschistes, stealing 

the algal photobiont for itself and parasitizing the Diploschistes. This lichen is an 

old-growth indicator (McCune and Rosentreter 2007).

Chemistry: Asci K/I-; cortex UV+ orange (rhizocarpic acid).

Comments: This is the only common yellow Acarospora on soils. Fulgensia species also produce yellow to orange thalli on arid soils, but they can be identified, 

even when sterile, by their K+ deep purple reaction. On gypsum soils one can find 

the uncommon crustose lichen Lecanora nodulosa (syn = L. reagens) 

which is normally white pruinose but 

occasionally will be light green and is 

more granular. 

to irregular disks but occasio

41

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s
42

Aspicilia aspera

Common name: Crustose coral lichen

Synonym: None

Description: Thallus thick crustose to cracked and fissured or erect-fruticose, light tan or somewhat reddish 

(dependent on substrate color), sometimes resembles 

old chewing gum. Branches cracked, fissured and solid 

(1-2 mm diameter), more or less circular or somewhat 

irregular in cross-section. No pseudocyphellae or rhizines. Apothecia extremely 

rare, colorless. Spores single-celled, colorless, 9-40 × 2-20 μm. Photobiont green 

(Trebouxia). 

Habitat: On limestone-derived or other highly calcareous soils.

Chemistry: KC+ yellow-orange (usnic acid only).

Comments: Aspicilia aspera is exclusively found on calcareous soils derived from 

limestone and red gypsum. Aspicilia species on soils can be very tricky to identify. 

Aspicilia aspera is best distinguished by its growth form and color. The more erect, 

narrowly branched, fruticose A. hispida is brown to green with pseudocyphellae 

appearing as conspicuous white spots on the thallus. Aspicilia desertorum form 

terrestris may be slightly fruticose on low carbonate soils but is more often a very 

fragile discontinuous whitish crust. Aspicilia reptans and A. filiformis

have prostrate, creeping, fruticose growth forms and a more northerly 

distribution. Aspicilia fruticulosa is very fruticose and has white spots on the lobe tips.

s Apothecia extremely

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Elevation

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43

Aspicilia desertorum form terrestris

Common name: Crusted aspicilia

Synonyms: Lecanora terrestrialis, L. desertorum

Description: Thallus crustose, thin chinky-areolate and 

discontinuous to more or less contiguous, white, whitish 

gray to gray-green, more or less pruinose, usually very 

fragile, at least partially attached to the soil. Apothecia 

very rare. Spores 8 per ascus, single-celled, colorless. 

Photobiont green (Trebouxia).

Habitat: Common on loamy to sandy soils Especially common on non-calcareous 

to mildly calcareous soils of the Colorado Plateau.

Chemistry: C-, K-, KC- or KC+ yellow-orange (usnic acid), P-. 

Comments: This species may take on a very fragile, creeping, fruticose growth 

form on non-calcareous, very sandy soils where it can be very abundant. Sometimes 

it appears as if it is peeling away from the substrate. The form found only on rock is 

form desertorum and is more continuous crustose and is frequently fertile. Diploschistes species and Aspicilia aspera both have much thicker thalli which are more 

continuous crustose in Diploschistes and more erect fruticose in A. aspera. This 

species is distinguished from Great Basin/Columbia Basin species A. reptans and A. 

filiformis by being more adnate to the 

surface and having a very thin thallus. 

It was first described from the steppes 

of Russia.

A

Photobiont green (Trebouxia

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Elevation

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44

Aspicilia filiformis

Common name: Ropy aspicilia

Synonym: None

Description: Thallus fruticose, olive, brown, or greenish when dry, turning bright to dull green when moist, 

creeping and mat-forming, branching in sections resembling beads on a string. Thallus attaching at several 

points along the lobes—less than 50% of the thallus 

is attached. Rarely pruinose. Lobes discrete, elongate, and stringy, typically short 

(5-10 mm), contorted, and irregular in length, up to 15 mm long, 0.4-1 mm wide, 

terete. Lobe tips distinctly different from the main thallus branches, often black and 

forked. Apothecia rare, 0.4-1.5 mm diameter. Spores 2-4 per ascus, single-celled, 

subglobose, variable in size, about 18-26 × 16-24 μm diameter. Photobiont green 

(Trebouxia).

Habitat: On organic matter, soils, and in non-calcareous grassland habitats.

Chemistry: All spot tests negative.

Comments: This species is similar to Aspicilia reptans, but the thallus of A. 

filiformis is more fruticose, with narrower, more elongate and stringy lobes and 

well-defined margins. Aspicilia californica (C+ red) is similar but has less distinct 

lobe tips and is not common in the Colorado 

Plateau region.

d stringy typically short

44

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Elevation

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Aspicilia fruticulosa

Common name: Coral lichen

Synonym: Lecanora fruticulosa

Description: Thallus fruticose, olive-green to brownish 

or gray, spherical, coarsely branched, 2 cm broad, free 

from the soil. Epruinose. Branches solid, more or less 

circular, dichotomous, very compact, short, thick (0.5 

mm), blunt, tipped with conspicuous whitish pseudocyphellae. Apothecia rare, with a lecanorine margin, variable in size. Disks blackish. 

Spores 3-4 per ascus, single-celled, broadly ellipsoid to spherical, colorless. Photobiont green (Trebouxia).

Habitat: Rare to locally common, vagrant on calcareous soils in shrub steppes, occasionally growing with Aspicilia hispida.

Chemistry: Medulla K- or K+ red.

Comments: Aspicilia hispida has scattered pseudocyphellae and pointed lobe tips, 

in contrast to the blunt lobe tips of A. fruticulosa. Pseudocyphellae on A. fruticulosa

are restricted to the lobe tips. 

The related species of Aspicilia

are basally attached to the soil, 

humus, or rock substrate. In contrast, 

A. fruticulosa is 

always vagrant and 

produces distinctly 

globose thalli. Fertile A. fruticulosa

specimens from 

Idaho and Utah 

have larger spores 

(30-20 × 25-15 μm) 

than other fruticose 

Aspicilia species.

4

-

d

)

e

cyphellae Apothecia rare w

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Elevation

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46

Aspicilia hispida

Common name: Desert vagabond

Synonym: Agrestia hispida

Description: Thallus fruticose, forming tiny, dull, 

olive-green to blue-green shrubby clumps up to 3 cm 

across, irregularly shaped, basally attached, erect, brittle, 

irregularly to dichotomously branched, with scattered 

laminal pseudocyphellae. Pseudocyphellae gray-green 

to yellowish gray. Branches short to elongate, terete to sometimes more or less flattened, tapering toward the edges. Lobe tips sharply pointed, solid, terete. Apothecia 

rare, sessile to short-stalked. Disks round to compressed, flat, smooth, dark gray, 

pruinose. Margins thick, persistent, smooth, concolorous with thallus. Spores 1-4 per 

ascus, single-celled, globose, colorless, large and variable in size. Photobiont green 

(Trebouxia).

Habitat: Over calcareous soils and pebbles in dry steppes. At first attached but often 

appearing vagrant when it is, in fact, attached to the soil.

Chemistry: All spot tests negative.

Comments: Aspicilia fruticulosa, a rarer member of this group, has white pseudocyphellae only on the branch tips (not laminally), and the tips are blunt rather 

than pointed. Vagrant species of Rhizoplaca and Xanthoparmelia are 

yellow-green (containing usnic acid 

in the cortex) and usually have flattened lobes.

ometimes more or less flat

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Elevation

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Aspicilia mastrucata

Common name: Mossy aspicilia

Synonym: Lecanora mastrucata

Description: Thallus crustose or prostrate with slightly 

erect fruticose lobe tips, olive green to brownish or 

gray, epruinose. Lobes up to 2 mm wide, solid, more 

or less circular or somewhat irregular in cross-section. 

Soredia occasional in irregular wart-like clumps. Cortex 

sometimes with pseudocyphellae. Apothecia rare with a lecanorine margin and 

blackish disk. Spores 4-8 per ascus, single-celled, 16-30 μm long. Photobiont green 

(Trebouxia).

Habitat: On mosses, soils, or old wood.

Chemistry: K+ red (norstictic acid), medulla C-.

Comments: This species has been overlooked by most ecologists and, when dry, 

is difficult to see. It is poorly known and collected in North America. Chemistry of 

this species is largely unknown but some are K+ red (often developing slowly). This 

species is mostly limited to growing over moss or other organic matter; even when 

found (rarely) growing on soils, the soil is high in organic matter. It is most often 

seen on clumps of Grimmia species that are growing on rock or shallow soils. It is 

most visible when moist and is more 

common in areas with mild, moist 

periods in the winter, such as in the 

Columbia Basin.

sometimes with pseudocyph

47

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Elevation

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Aspicilia reptans

Common names: Creeping rimmed lichen, beaded 

string lichen

Synonym: Lecanora reptans

Description: Thallus fruticose, ranging in color from 

whitish to bluish gray, greenish when moist, looks like 

dead organic matter when dry. Sometimes pruinose. 

Areolae creeping and attaching at several points along 

the lobes. Lobes strongly convex or almost terete, clumped but not mat-forming, discrete, like beads on a string, 0.5-1.4 mm. Lobe tips not clearly differentiated. Lower 

cortex white with sparse, short rhizines. Less than 50% of the thallus is attached. 

Apothecia rare. Disks black. Margins sometimes absent, concolorous with the thallus. Spores 8 per ascus, single-celled, small. Photobiont green (Trebouxia).

Habitat: Shortgrass prairie, often on non-calcareous soils and organic matter.

Chemistry: All spot tests negative.

Comments: This species can be common in some sites and can form a continuous 

cover in pristine sites. It is very vulnerable to trampling. Aspicilia filiformis and A. 

californica (K+ red) are similar but have more distinct lobe tips and are not common in the Colorado Plateau region. Megaspora verrucosa has a similar color but is 

found on wood and organic matter and typically is fertile with deeply 

sunken apothecia, very large spores (> 30 μm), and a much thicker 

thallus. Aspicilia mastrucata often grows on mosses over thin soils or 

rock but rarely on soils.

ed but not mat forming dis

48

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Elevation

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49

Buellia elegans

Common name: Button lichen 

Synonym: None

Description: Thallus generally crustose, upper surface 

whitish pruinose, forming flat-lying rosettes up to about 

2 cm diameter. Margins lobate and adnate. Lobes about 

1 mm broad. Apothecia attached to the soil, black, lecideine, to 1 mm diameter. Apothecial margin concolorous 

with disk but at first with a thin, superficial, thalloid coating. Spores 8 per ascus, 

dark brown, mostly 2-celled, 13-18 × 6-9 μm. Photobiont green (Trebouxia).

Habitat: Dry, open, calcareous areas in grasslands and on soils in semiarid areas.

Chemistry: Thallus K+ dirty yellow, P-.

Comments: The spores are brown and 2-celled to rarely many-celled, and the apothecia lack a lecanorine rim. Externally, Lecidea, Lecidella, Rhizocarpon, and other 

genera in the Lecideaceae family are very similar but have different spores. This 

genus is differentiated by the above microscopic characters as well as the dark color 

of the hypothecium and epithecium, and thicker spore walls. 

with disk but at first with a t

49

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50

Buellia punctata

Common name: Tiny button lichen

Synonyms: Amandinea punctata, Buellia punctiformis

Description: Thallus generally crustose, cracked or 

areolate, dirty gray to brownish, green when wet, thin 

and barely perceptible to moderately thick. Epruinose. 

Apothecia black, lecideine, 0.2-0.5 mm diameter, flat 

to convex. Margin thin and black, often disappearing 

in maturity, attached to the substrate. Exciple uniformly pigmented dark brown. 

Spores 8 per ascus, dark, mostly 2-celled (or more), 11-16 × 6-8 μm, cell walls not 

constricted. Photobiont green (Trebouxia).

Habitat: Twigs and bark of old wood are preferred habitats, but it can also be found 

on rock, soils and organic matter.

Chemistry: All spot tests negative.

Comments: Buellia punctata in aridlands is mostly found on organic matter, unlike 

B. elegans which is mostly found on calcareous soils. Buellia punctata is more 

frequent in old growth habitats and is an indicator of organic matter accumulation 

and lack of recent fire.

pigmented dark brown

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Elevation

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51

Caloplaca tominii

Common name: Tomin’s orange lichen

Synonym: None

Description: Thallus crustose, adnate, bright orange 

to yellow-orange. Thallus surface breaks into soredia. Epruinose. Apothecia usually yellow to orange, 

0.5-1.5(5) mm diameter. Margins usually lecanorine. 

Spores 2-celled, colorless, with a conspicuously thickened cell wall, pushing the cell cavities (locules) to the ends or “poles”, therefore 

called polarilocular, 16-17 × 8-9 μm. Photobiont green (Trebouxia).

Habitat: On calcareous and slightly calcareous soils.

Chemistry: Thallus K+ purple-red or violet blue.

Comments: This species is easily determined by the mostly sorediate (powdery) 

surface of the thallus. Caloplaca species are generally more orange than yellow 

compared with the egg-yolk yellow lichens, such as Candelariella, which contain 

different pigments and are K-. The polarilocular spores are the confirming character, 

although in a few species, the cell wall is so thin that the spores resemble ordinary 

2-celled spores. This species was originally described from the steppes of Asia and 

is an early successional species that can recolonize sites 1-3 years after fire and other 

types of disturbance. The presence of this lichen indicates that some 

calcium is in the soil—sometimes just 

a trace of calcium carbonate on the 

soil surface.

ened cell wall pushing the c

51

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52

Candelariella citrina

Common name: Egg yolk soil lichen

Synonym: Candelariella terrigena

Description: Thallus crustose or squamulose, varying 

from granular to areolate with slightly lobed areolae, 

more yellow than green, especially when dry. However, 

when wet it turns lightly green-yellow, often appearing as scattered yellow blobs on the soil, adnate, rarely 

forming lobed rosettes, often scanty, sometimes very scanty or growing only within 

the substrate. Epruinose. Lacking reproductive structures. Apothecia lecanorine, 

0.4-0.7 mm diameter. Margins thin or thick, often discontinuous, thallus-colored. 

Disks yellow to brownish yellow. Spores 8 per ascus, colorless, ellipsoid, singlecelled or, rarely, 2-celled (sometimes appearing to be 2-celled because of large oil 

drops), 14-18 × 6-8 μm. Photobiont green (Trebouxia). 

Habitat: On soils, mosses, other lichens, organic matter, or dying vegetation.

Chemistry: C-, K- or K+ pale rose, KC-, P-, UV+ dull, dark orange (calycin).

Comments: Bright yellow species of Acarospora and Pleopsidium sometimes resemble Candelariella, but their apothecia are 

usually sunken into thallus areolae, and their 

asci generally contain hundreds of spores. 

Because they contain rhizocarpic acid instead 

of calycin, their UV fluorescence is much 

brighter orange.

nty or growing only within

52

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Elevation

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53

Cladonia fimbriata

Common name: Trumpet lichen

Synonym: Cladonia major

Description: Primary thallus squamulose, persistent, 

green to whitish gray. Squamules up to 6 mm long and 

4 mm wide, lobe margins toothed to wavy, coarsely 

sorediate (especially under lobe margins). Podetia stalks 

sometimes breaking into masses of soredia. Stalks 

6-30(40) mm tall, 1-2 mm wide, green to whitish gray, unbranched, with narrow, 

trumpet-shaped cups. Cups 2-6 mm wide. Margins entire or minutely toothed. 

Soredia abundant, flour-like, sometimes enlarging, later disintegrating and exposing 

the white medulla. Apothecia uncommon, brown, up to 1.5 mm in diameter. Spores 

8 per ascus, oblong, single-celled, colorless, 8-14 × 3-4.4 μm. Pycnidia at cup margins, nearly globose. Photobiont green (Trebouxia).

Habitat: On soils or rotting wood, in sun or partial shade.

Chemistry: Thallus K-, P+ red (fumarprotocetraric acid).

Comments: Cladonia fimbriata

must be carefully distinguished 

from C. chlorophaea by the 

presence, in the 

former, of powdery 

soredia more than 

one layer deep on 

the lower (external) 

portions of the cups; 

in C. chlorophaea 

the soredia are 

more granular and 

typically arranged 

in a single layer and 

the cups are more 

broadly flaring. 

The cups on C. 

fimbriata are longer 

and narrower than 

C. chlorophaea or 

C. pocillum. 

6-30(40) mm tall 1-2 mm w

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;

d

r
54

Cladonia pocillum

Common names: Rosette pixie-cup, carpet pixie-cup

Synonym: Cladonia pyxidata var. pocillum

Description: Primary thallus squamulose, olive green 

to brownish green. Epruinose. Squamules persistent, 

crowded, large, thick, horizontally spreading, contiguous 

to overlapping, forming colonies of rosettes around the 

base of the podetia. Podetia are poor or lacking. When 

present, podetia originate from upper surface of primary squamules, short, cupforming, or occasionally with marginal proliferations, grayish green to olive-green 

or becoming brownish. Cups initially narrow, becoming goblet-shaped; cup interior 

closed. Podetia and cups covered with small to coarse peltate squamules (umbrellashaped and attached at the lower surface with a short stalk). Rhizines lacking. 

Apothecia rare, brown, along margins of cups, up to 3 mm wide. Spores 8 per ascus, 

single-celled, colorless. Photobiont green (Trebouxia).

Habitat: Very common in dry habitats, especially on calcareous soils. On soils and 

soils over rock, often in highly exposed, sunny and windy sites. Common in cooler 

sites within the Colorado Plateau.

Chemistry: Thallus C-, K-, KC-, P+ red; medulla UV-.

Comments: Basal squamules are always present and are greenish on 

the upper side and lighter to white on the lower side. They also have 

fruticose portions (podetia) that are erect but in some arid conditions 

are reduced and contorted.

squamules short cup

54

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55

Collema coccophorum

Common names: Tar jelly lichen, collema

Synonyms: Collema dubium, C. novomexicanum

Description: Thallus gelatinous, non-stratified, minutely foliose or lacking foliose lobe margins, usually 

dominated by black, globose isidia. Epruinose. Forms 

hemispherical colonies up to about 3 cm diameter. Lobes 

0.5-3 mm broad, 170-350 μm thick, when moist sometimes distinctly rosette-shaped. Apothecia uncommon, rimmed, brown, and more or 

less flat, 0.2-2 mm. Spores mostly 2-celled. Photobiont blue-green (Nostoc).

Habitat: On calcareous soils. This species of Collema is more common in the Colorado Plateau region and the Sonoran Desert than in the Great Basin.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Collema coccophorum is commonly the 

dominant lichen on calcareous soils and commonly grows in a lime-loving community that includes Psora decipiens and Placidium species, although it is often found 

at lower densities on less calcareous soils. It co-occurs with Collema tenax which 

can be distinguished in the Colorado Plateau region and in the warm deserts by its 

attached rosette growth form and radiating lobes along the thallus margin. In the Columbia Basin, the two species may not 

be distinguishable by thallus morphology alone, but C. tenax predominates. 

times distinctly rosette shap

55

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-
56

Collema tenax

Common names: Soil jelly lichen, collema

Synonyms: Collema cristatellum, C. pulposum

Description: Thallus gelatinous and minutely foliose or 

lobate, dark olive-green to black, often forming small, 

rounded or flat rosettes a few cm diameter. Thallus 

margins lobate and thicker near the terminus. Globose 

isidia resembling little balls may or may not be present, 

closely attached to partly curving up, dark olive-green to black. Apothecia infrequent, rimmed, reddish brown to brownish black, and more or less flat. Spores 2-8 

per ascus, mostly 4-celled, colorless, 17-30 × 8.5-13 μm. Photobiont blue-green 

(Nostoc).

Habitat: On more or less calcareous soils.

Chemistry: All spot tests negative.

Comments: This nitrogen-fixing lichen is the most variable and most common 

species of this genus and attains the greatest abundance on mildly to moderately 

calcareous soils. On highly calcareous soils it tends to be less abundant than C. coccophorum. In warm desert and Colorado Plateau specimens, C. tenax tends to be less 

isidiate with radiating thalli in a rosette and has marginal lobes that are wider near 

the tip. Collema coccophorum has more erect thalli and is generally 

covered in bulbous isidia. In the Great Basin and Columbia Basin, C. 

tenax specimens may be virtually identical to C. coccophorum. However, spores of C. coccophorum are 2-celled.

black Apothecia infre500

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, p p
57

Diploschistes diacapsis

Common name: Desert crater lichen

Synonyms: Diploschistes albissimus, Urceolaria albissima

Description: Thallus very thick, crustose, light gray 

due to heavy pruina, often with an undulating appearance, greater than 5 cm diameter. Areolae up to 2.5 mm 

diameter. Rhizines lacking. Apothecia usually present, 

broad (up to 2.5 mm) and immersed, black or pruinose gray. Spores 4-8 per ascus, 

many-celled, 20-38 × 9-17 μm. Photobiont green (Trebouxia).

Habitat: Common on gypsiferous soils in the cool deserts, coastal Sonora and 

southern California grasslands and chaparral but may occur on various soils farther 

south and east.

Chemistry: C+ dark red, K+ yellow to purple, KC+ red, P-.

Comments: Diploschistes diacapsis is an excellent gypsum indicator in the Colorado Plateau region. It can occasionally form very impressive large populations and 

may dominate local areas. It typically co-occurs with Psora decipiens, Fulgensia 

bracteata, and Squamarina lentigera. Diploschistes diacapsis can be distinguished 

by its very thick (~ 2 mm), sometimes undulating crustose thallus and sunken 

rimmed apothecia. It looks similar to D. muscorum, which is epruinose, 

generally smaller and flatter with a 

thinner thallus, and occurs almost 

exclusively on non-calcareous soils.

broad (up to 2 5 mm) and im

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58

Diploschistes muscorum

Common names: Cowpie lichen, crater lichen

Synonym: Diploschistes canadensis

Description: Thallus crustose, light gray, flat to somewhat undulating or with a warty texture. Individual 

areolae usually less than 2 mm wide, often with margins 

only partially attached to the substrate, continuous, sometimes pruinose. Apothecia usually present, 

rimmed and sunken, less than 1.5 mm diameter and immersed, black or pruinose 

gray. Spores 4 per ascus, many-celled, large (18-32 × 6-15 μm). Photobiont green 

(Trebouxia).

Habitat: On non-calcareous soils and mosses or parasitic on Cladonia species.

Chemistry: C+ pink to red, K+ yellow to purple, P-.

Comments: Diploschistes muscorum is found throughout the North American aridlands, at all elevations and especially at northerly latitudes on non-calcareous soils 

and may also occur at rather low altitudes. It commonly co-occurs with Cladonia 

fimbriata or C. chlorophaea, which it may initially parasitize, and Acarospora schleicheri, which may parasitize it. Diploschistes diacapsis can be distinguished from D. 

muscorum by its very thick (~ 2 mm), undulating, crustose thallus, and preference 

for gypsiferous soils. Diploschistes muscorum, which is not pruinose, 

is darker gray and generally smaller and flatter with a thinner thallus 

and occurs almost exclusively on 

non-calcareous soils.

ersed black or pruinose

58

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59

Endocarpon pusillum

Common name: Scaly stippled lichen

Synonym: Endocarpon schaereri

Description: Thallus squamulose, tan to light or dark 

brown. Epruinose. Squamules scattered to rarely contiguous, attached to the substrate to curving up at the 

edges, often greater than 1.5 mm diameter. Rhizines 

black, not apparent without removing the soil. Lower 

surface black or pale gray-brown. Soredia and isidia lacking. Perithecia common, 

immersed, dome-shaped, appearing as black wart-like structures, generally apparent only by a darkened ostiole. Spores 2 per ascus, many-celled, brown (rarely pale 

brown at maturity), 24-38 × 10-18 μm. Photobiont green (Stichococcus).

Habitat: On both calcareous and non-calcareous soils and rocks.

Chemistry: All spot tests negative.

Comments: The presence of algal cells in the perithecium and the many-celled 

spores immediately distinguishes Endocarpon pusillum from similar species of 

Placidium. The less scattered and more clustered specimens of E. pusillum can be 

mistaken for Staurothele which also has green algae in the perithecia but is truly 

crustose, having no lower cortex or upward-curving squamules. The perithecia in E. 

pusillum are larger and rise above the cortex more than they do in Placidium or Catapyrenium species. These perithecia are usually visible 

without a hand lens.

surface black or pale gray b

59

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60

Fulgensia bracteata

Common name: Sulfur lichen 

Synonym: Caloplaca bracteata

Description: Thallus crustose, granular to areolate, 

orange-yellow (parts may be white due to visible hypothallus), pruinose. Thallus margin lacks distinct lobes. 

Apothecia common, orange when mature, usually about 

1 mm diameter. Spores single-celled, colorless, 11-15 × 

5.5-8 μm. Photobiont green (Trebouxia). 

Habitat: On calcareous soils and especially gypsiferous soils in cold desert or high 

elevation sites.

Chemistry: C-, K+ red or purple, KC-, P-.

Comments: Fulgensia bracteata is distributed from high to low elevations, including arctic tundra and cool deserts. In the arid regions it is occasionally found on calcareous soils but becomes quite abundant on gypsiferous soils where it co-dominates 

with Psora decipiens. Fulgensia species are continuous crustose and yellow, in contrast to the more foliose Caloplaca and Candelariella, which tend to be more orange 

and are much more fragile and may be discontinuous. The most abundant species 

of Caloplaca and Candelariella are often lacking apothecia. Fulgensia desertorum

is similar but tends toward a paler yellow due to a white hypothallus, 

and has smaller, darker, rust-colored 

apothecia (1 mm) and clearly lobate 

thallus margins.

60

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Heppia lutosa

Common name: Common soil ruby lichen

Synonym: Solorinaria despreauxii

Description: Thallus squamulose, dark olive to brownish, circular in outline with the margins entire or becoming granular and irregularly toothed. Epruinose. Cortex 

well-developed, and some specimens have a loosely 

organized lower cortex. Medullary hyphae arranged 

vertically like a string of beads. Apothecia red-brown (ruby-red when wet), immersed in depressions in the thallus, sometimes very deeply concave. Spores 8 per 

ascus, colorless, single-celled, ellipsoid, about 20 × 10 μm. Photobiont blue-green 

(Scytonema), usually in vertical rows within the thallus. 

Habitat: On limey soils, occasionally on soil in rock crevices and under overhanging rocks in desert and steppe.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Peltula richardsii, which is very similar, has tiny, more numerous (> 60) spores per ascus and larger squamules (> 3 mm), 

occurs in colonies, and lacks an upper cortex (not gray). Placidium species contain 

green algae and have buried perithecia that show up as black dots on the surface. 

Heppia lutosa is generally darker olive than the gray Placidium species 

and often occurs as a single squamule, while Placidium species are 

always in small colonies. Heppia conchiloba has more upturned lobe 

margins covered with soredia. 

vertically like a string of bea

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62

 Lepraria spp.

Common name: Dust lichen

Synonyms: Lepraria zonata and a dozen more

Description: Thallus crustose, blue-gray, gray, green, 

yellowish green, or white, coarsely granular sorediate, 

often forming distinctive rings or concentrically arranged in “zones” when growing on soils or rock. Thallus margins indistinct or, less commonly, clearly defined 

but without upward-curving lobes. Sterile, consisting of nothing but a continuous 

layer of soredia (actually, consoredia which are spherical, often fuzzy aggregations 

of a few individual soredial particles and look like very tiny cotton balls). Apothecia 

not present. Photobiont green (Trebouxia). 

Habitat: On soil in shaded microhabitats, such as under or adjacent to grasses and 

shrubs, often on north-facing slopes at low elevations or in alpine tundra. Found 

only under overhanging rock in the Colorado Plateau region.

Chemistry: Variable by species.

Comments: Lepraria species are often confused with other genera of sterile soil 

crusts such as Ochrolechia and Pertusaria. This is a difficult group of lichens to 

identify and can, at times, be an early colonizer species in some habitats. Distribution by species is poorly known. This group of lichens needs further 

study and, although common, they 

are not well understood.

nothing but a continuous

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L. neglecta
63

Leptochidium albociliatum

Common name: Whiskered jelly lichen

Synonyms: Leptogium albociliatum, L. pilosellum, 

Polychidium albociliatum

Description: Thallus foliose, gelatinous, greenish to 

slate gray to brownish black, weakly stratified with a 

middle layer of horizontal hyphae between two algal 

layers. Lobes 3-5 mm wide, with small but conspicuous white hairs abundant on lobe margins and exciple (10x hand lens), occasionally 

on the upper surface and isidia. Isidia present, granular to scale-like, occasionally 

cylindrical. Apothecia lecanorine, fairly common. Spores colorless, 2-celled, 18-26 

× 5-9 μm. Photobiont blue-green (Scytonema).

Habitat: On mosses, soils or soil over rock, widespread, fairly common in moist to 

arid environments.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Leptochidium superficially resembles 

some of the isidiate Leptogium species, such as L. saturninum and L. burnetiae,

which have abundant white hairs on the lower surface. The stiff white “whiskers” on 

the lobe margins of Leptochidium distinguishes them. The presence of definite algal 

and medullary layers in the thallus is also diagnostic. In aridlands, it is 

an indicator of old growth conditions 

and it appears to be readily disturbed 

by livestock grazing and trampling.

ous white hairs abundant on

63

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64

Leptogium lichenoides

Common name: Tattered jellyskin

Synonym: Tremella lichenoides

Description: Thallus gelatinous (non-stratified), foliose, 

forming small, brownish black cushions. Lobes fairly 

wide (1-4 mm), wrinkled, upright, with edges that have 

finely divided, almost cylindrical, isidia-like outgrowths. 

Lobe tips erect, narrow (mostly 2 mm wide), grayish to 

brownish, lobulate or finely fringed. Upper surface generally with raised wrinkles 

visible with a hand lens (10x), interior of loosely interwoven hyphae. Rhizines lacking. Apothecia occasional, brownish red to black, concave, 0.2-0.7 mm diameter. 

Spores 4-8 per ascus, colorless, 4-celled to many-celled, 18-45 × 11-16 μm. Photobiont blue-green (Nostoc). 

Habitat: On soils and among mosses.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Leptogium and Collema have much 

in common and are sometimes difficult to distinguish in the field, especially when 

they are moist and swollen. However, Leptogium species do not enlarge when wet 

as much as Collema species. On the whole, species of Leptogium are grayer (often 

steel-gray) or more reddish brown when dry, with a smoother, more 

skin-like texture. Collema is never as shiny, probably because it has 

no upper cortex. Leptogium lichenoides is highly variable in form, but 

always has dissected lobes that have isidiate or fringed lobe margins.

ally with raised wrinkles

64

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65

Massalongia carnosa

Common name: Little-lobed lichen

Synonym: Pannaria carnosa

Description: Thallus foliose, isidiate to lobulate, a 

distinctive chocolate-brown color, rosette-forming. 

Upper cortex shiny when dry. Lobes foliose or subfoliose, up to 5 mm long. Margins distinctively finger-like, 

lobate. Marginal lobes similar in length and radiating 

out like fingers on a hand. Lower surface pale with sparse, dark rhizines. Apothecia 

rare, reddish brown to black, laminal or marginal, up to 2 mm diameter. Spores 8 per 

ascus, colorless, generally 1- to 2-celled, 11-27 × 4.5-8.5 μm. Photobiont blue-green 

(Nostoc).

Habitat: Moist sites, often on mosses and soils on north-facing slopes.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Widespread but seldom common, this 

late successional species is less frequent in arid deserts than in the more moist Great 

Basin sites and grassland habitats. It is an old growth indicator in aridlands. It has a 

distinctive chocolate-brown color and, once seen, is easy to identify. It sometimes 

has pruina on the margins of the lobes. It is readily 

disturbed by livestock grazing and 

trampling.

out like fingers on a hand L

65

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66

Megaspora verrucosa

Common names: False sunken disk lichen, volcano 

lichen

Synonyms: Pachyospora verrucosa, Lecanora verrucosa

Description: Thallus crustose, gray-green to cream, 

thick, more or less densely white-pruinose, continuous 

or more or less dispersed in irregular patches. Apothecia 

with black, mostly sunken disks, 0.5-1.5 mm diameter, sometimes lecanorine with 

a thick margin. Spores 8 per ascus in two rows, colorless, single-celled, ellipsoid, 

thick-walled, 30-65 × 16-36 μm. This genus is named for its large spores. Photobiont green (Trebouxia).

Habitat: Widespread but infrequent on soils and mosses, especially in calcareous 

habitats. It occurs from deserts to microhabitats in forests of all kinds and into the 

alpine and talus slopes. Always on organic substrates.

Chemistry: All spot tests negative.

Comments: When sterile, M. verrucosa looks like Diploschistes which is C+ red, 

or Aspicilia species which can also be C+ red. This large-spored species is distinctive from similarly colored Aspicilia species due to the much larger spores and much 

broader habitat preference. It also has thicker spore walls and abundantly branched paraphyses. The M. verrucosa thallus is also much 

thicker and more robust than Aspicilia species 

and lacks well-defined lobes.

ometimes lecanorine with

66

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67

Ochrolechia upsaliensis

Common names: Saucer lichen, cudbear

Synonym: Psora upsaliensis

Description: Thallus thick crustose, white to cream, 

coarsely granular to wrinkled or covered with small, 

thick, wart-like growths, more or less divided into many 

short, irregular, cylindrical, often brittle branches (coralloid). Pruinose. Apothecia abundant, generally pink or 

orange, sessile, mostly 0.6-2 mm diameter. Disks concave to flat, pale yellow to 

buff, pruinose, more or less cracked. Margins entire, thick, lecanorine, concolorous 

with thallus. Spores 8 per ascus, ellipsoid, colorless, single-celled, large (30-68 × 

23-37 μm). Photobiont green (Trebouxia).

Habitat: Often growing over Selaginella (spike mosses) and in arid habitats and 

sites with shallow soils over rock. More common in cold habitats.

Chemistry: All spot tests negative on the thallus, apothecia C+ yellow.

Comments: This lichen is widespread and common, mainly growing over bryophytes, but in some dry forest sites it will grow over organic matter and detritus 

and cover large areas. This species was used as a dye for wool. The common name 

“cudbear” is derived from this use. It grows thickly and densely over spike mosses 

which tend to decompose slowly in 

arid habitats. Ochrolechia upsaliensis

can be used as an indicator of the lack 

of fire at a given location.

orange sessile mostly 0 6 2

67

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68

Peltigera rufescens

Common names: Field dog lichen, felt lichen

Synonyms: Peltigera canina var. rufescens, P. canina

Description: Thallus foliose, gray to grayish brown 

or brown, pruinose, forming approximately circular 

rosettes 5-15 cm diameter (occasionally much larger). 

Lobes narrow (usually < 1 cm wide), concave. Upper 

surface with abundant, thick, felt-like hairs often extending to center of thallus. Lower surface with dark veins and thick rhizines. Apothecia 

common, lecanorine, on raised, narrow marginal lobes which curl back toward the 

center of the thallus, up to 5 mm diameter. Disks orange-brown, red-brown, dark 

brown, or black. Spores 8 per ascus, colorless to pale brown, very narrowly cigarshaped to needle-shaped, 2- to 6-celled, 30-70 × 3-5 μm. Photobiont blue-green 

(Nostoc).

Habitat: On mosses, mineral soils, bare ground, or organic matter.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Peltigera rufescens is more common 

in more mesic habitats (i.e., higher elevations and latitudes). It commonly co-occurs 

with Cladonia species and mosses such as Ceratodon purpureus, Brachythecium

species or Syntrichia ruralis. Peltigera rufescens has many more fine, 

felt-like hairs than P. kristinsonii which can have smooth, shiny portions of the upper thallus and lobe tips and a roughened appearance.

nd thick rhizines Apothecia

68

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69

Peltula richardsii

Common name: Giant rock-olive

Synonym: Heppia richardsii

Description: Thallus squamulose, dark olive to olivebrown with rather round lobes, epruinose. Squamules 

attached to the substrate at the center by a clump of 

rhizines or a single holdfast, 2-6(10) mm diameter. 

Apothecia sunken into the center of the thallus and level 

with the surface or slightly concave. Disks red-brown (looking like a pimento in an 

olive), 0.5-3(5) mm diameter. Spores up to 100 per ascus, colorless, single-celled, 

tiny (6.5-8.5 μm diameter). Photobiont blue-green (Anacystis).

Habitat: On soils with high calcium levels, particularly in places where water runs 

across the surface during heavy storms.

Chemistry: All spot tests negative.

Comments: This is a nitrogen-fixing lichen. Peltula superficially resembles the 

earth or rock scale lichens (Psora and Placidium, which contain green algae) and 

Heppia. The latter also contains cyanobacteria but from a different genus (Scytonema), and the asci contain only 8 spores. Peltula patellata has a similar appearance 

but tends to be much smaller in overall size, and the apothecia are much smaller. 

Peltula species are more common in 

the warmer microhabitats of the Colorado Plateau and are common in the 

warm deserts of North America.

with the surface or slightly c

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69
70

Phaeorrhiza nimbosa

Common name: Brown-fuzz lichen

Synonyms: Rinodina nimbosa, R. phaeocarpa

Description: Thallus squamulose, dark brown to 

yellow-brown and frequently pruinose, appearing gray 

to whitish when dry and darkening when wet. Squamules almost continuous with lobed margins, sometimes 

overlapping, generally greater than 1 mm broad. Marginal lobes 0.2-0.5 mm broad. Lower surface with rhizine-like hyphae. Apothecia 

extremely abundant and crowded, immersed when young, becoming lecanorine, 

with flat, dark brown to black disks and thick margins when mature, 0.4-1.5(2.5) mm 

diameter—the apothecia are distinctive. Spores 8 per ascus, brown, 2-celled, with 

more or less uniformly thin walls, 17-24 × 7-12 μm. Photobiont green (Trebouxia).

Habitat: On dry, calcareous soils.

Chemistry: All spot tests negative.

Comments: The only other common species of Phaeorrhiza in North America is P. 

sareptana, a lichen found mainly in the mountains, prairies, and steppes of the dry 

interior. Its thallus is distinctly squamulose with black, convex, marginless, lecideine 

apothecia and K+ violet reaction on the lower surface. Phaeorrhiza nimbosa is more 

common in old growth sites and in 

alpine areas (Brodo et al. 2001).

e-like hyphae Apothecia

70

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Elevation

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71

Physconia muscigena

Common name: Ground frost lichen

Synonym: Physcia muscigena

Description: Thallus narrow foliose, from pale green or 

gray-brown to dark brown, irregular or (rarely) circular 

in outline, 5 cm or more diameter. Lightly to heavily 

coated with pruina that resemble hoarfrost. Pruina disappear when moist, and the thallus turns a brighter green. 

Lobes curving up at the edges, elongate or short, dissected, distinctly overlapping 

like shingles and somewhat hollowed, flattened, up to 4 mm wide. The underside 

is black with scattered black bottle-brush-like rhizines which are obvious and 

abundant. Loosely attached to substrate. Apothecia common with a smooth margin 

becoming lecanorine, up to 5 mm diameter. Disks dark brown and usually whitened 

with pruina. Spores 8 per ascus, brown, single-celled, usually with thin, more or less 

uniform walls except for a thickened cell wall in young spores, 24-33 × 12-17 μm. 

Photobiont green (Trebouxia).

Habitat: A common species of open grasslands on lime-rich soils, moss mats, and 

at the base of shrubby vegetation. Common in the Great Plains and Columbia Basin 

and in alpine areas.

Chemistry: All spot tests negative.

Comments: This species is as easily damaged as many fruticose 

lichens when dry. Many habitats have lost this species due to livestock 

grazing and trampling.

Lobes curving up at the edg

71

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Elevation

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72

Physconia perisidiosa

Common name: Crescent frost lichen

Synonyms: Physconia farrea, P. grisea, Parmelia farrea

Description: Thallus foliose, gray to dark brown, usually with a mauve or purplish tinge, irregular in outline, 

more or less loosely attached. Lobes short, more or 

less imbricate, often pruinose (especially at tips), nonpruinose parts more or less glossy, 0.5-1.2 mm wide. 

Soralia lip-shaped. Marginal lobes often confluent and densely isidiate in center of 

thallus. Medulla white. Underside whitish and lacking the cortex at tips, becoming 

blackish and corticate within, with black, bottle-brush-like rhizines. Apothecia very 

rare, lecanorine. Disks brown or white pruinose, often with lobules or soredia on the 

margins. Exciple lecanorine, often with sorediate lobules. Spores 2-celled, brown, 

generally greater than 24 × 13 μm. Photobiont green (Trebouxia).

Habitat: On bark, less frequently on soils or rock, in sites protected from trampling.

Chemistry: All spot tests negative.

Comments: The discrete soralia, usually on the lobe tips, distinguishes this species 

from the more common bark-dwelling Physconia detersa, P. enteroxantha, and P. 

isidiigera, in which the soredia are strictly marginal or rarely occur on lobe tips. In 

P. leucoleiptes, one finds somewhat crescent-shaped soralia containing 

finer soredia. This species is very 

vulnerable to trampling when dry.

ensely isidiate in center of

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Placidium lacinulatum

Common name: Brown stipplescale

Synonyms: Catapyrenium lacinulatum, Dermatocarpon 

hepaticum

Description: Thallus squamulose, brown, 3-6 mm wide, 

separate to imbricate, round to lobate, epruinose. Lobe 

margins adnate to slightly upturned. Undersurface pale, 

anchored tightly to the soil by a bundle of usually pale 

rhizines. Perithecia frequent and visible as occasional black dots which are upraised 

pores on the thallus surface. Spores 8 per ascus, single-celled, colorless, elliptical, 

15-19 × 7.5-9.5 μm. Photobiont green, chlorococcoid (Pleurococcus or Myrmecia).

Habitat: Often on shallow, silty soils in arid and non-arid habitats.

Chemistry: All spot tests negative.

Comments: Placidium is among the most abundant lichen genera of the North 

American deserts and occupies a variety of habitats. The P. squamulosum-lacinulatum-lachneum group is very difficult to distinguish in the field; they require 

examination under a microscope for a firm identification. Placidium squamulosum

lacks rhizines and is anchored by numerous, small-diameter, rhizoidal hyphae, while 

P. lacinulatum is anchored by thick rhizines. The underside of P. lachneum is dark, 

while that of P. lacinulatum is lightcolored. This lichen is often found 

with Collema tenax growing between 

the individual squamules.

rhizines Perithecia frequent

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Placidium squamulosum

Common names: Stipplescale lichen, earthscale

Synonyms: Catapyrenium squamulosum, Dermatocarpon hepaticum

Description: Thallus squamulose, brown when dry 

and green when wet. Nearly completely attached to the 

substrate or the margins slightly upturned. Epruinose. 

Squamules separate to imbricate, more or less round 

to slightly lobate, size variable (2-7 mm). Undersurface pale, entire undersurface 

attached by rhizoidal hyphae. Perithecia frequent and visible as upraised black pores 

on the thallus. Spores 8 per ascus, single-celled, ellipsoid, 12-16 × 5.5-7.5 μm. Photobiont green, chlorococcoid (Pleurococcus or Myrmecia).

Habitat: Common on soils in arid and other regions of North America.

Chemistry: All spot tests negative.

Comments: See the comments for Placidium lacinulatum. Placidium squamulosum 

is very common in the Colorado Plateau region but is less common in northern arid 

regions. This species appears to be an early colonizer of disturbed sites. 

pale entire undersurface

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Placynthiella spp.

This includes: Placynthiella icmalea, P. uliginosa, P. 

oligotropha, and Placynthium nigrum

Synonyms: Lecidea, Saccomorpha

Description: Thallus crustose, brown to almost black, 

often tinged yellowish green when wet, coarsely granular, covered with small wart-like growths. Granules 

100-300 μm diameter, more or less contiguous or 

dispersed. Surface rugose-roughened, dull. Soredia absent. Epruinose. Apothecia 

rare, black with a black rim, at first flat with a more or less elevated true exciple, occasionally becoming convex and lacking a well-defined edge, 0.2-0.5 mm diameter. 

Spores 8 per ascus, single-celled, colorless, ellipsoid, thin-walled, often containing 

a few large oil drops, 10-15 × 4-7 μm. Photobiont green (Chlorella).

Habitat: On bare peaty or sandy soils, well-rotted lignum, or organic matter, usually in the open or in partial shade in cold deserts and more moist habitats.

Chemistry: All spot tests negative.

Comments: Placynthiella species are common over organic matter and are easily 

overlooked due to their thin covering over the substrate and their drab brown color 

which is often similar to the color of the substrate. Placynthiella is more browncolored than dense cyanobacterial 

crusts and appears isidiate with a 10x 

hand lens.

dispersed Surface rugose-ro

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P. oligotropha
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Psora cerebriformis

Common names: Brain scale, cerebral fishscale, fissured scale lichen

Synonym: Lecidea cerebriformis

Description: Thallus squamulose, usually white due 

to dense pruina, otherwise pale brown to olive-brown. 

Entire colonies of squamules in a hemispherical shape 

resembling a brain. Pruinose. Squamules are usually 

very convex, fissured or cracked on the surface, folded and imbricate, but occasionally flat, mostly 2-6 mm across. Rhizines lacking. Apothecia common and black or 

sometimes green, hemispherical, borne on squamule margins, up to 2 mm diameter. 

Spores 8 per ascus, single-celled, colorless, ellipsoid, 7-18 × 5-9 μm. Photobiont 

green (Myrmecia). 

Habitat: On calcareous soils, particularly at middle elevations.

Chemistry: C-, K+ yellow or red, KC-, P-.

Comments: Psora cerebriformis is particularly common on calcareous soils in 

cool deserts and at higher elevations in warm deserts. It is a common associate of P. 

decipiens, Toninia sedifolia, Fulgensia species, Collema tenax, and C. coccophorum. 

Highly pruinose specimens of P. crenata may resemble this species but tend to have 

smaller apothecia and larger squamules which are smooth except for 

the single depressed dimple in the 

center of the thallus.

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Psora crenata

Common names: Brick scale, crenate fishscale lichen

Synonyms: Lecidea coroniformis, L. crenata

Description: Thallus squamulose, pink to brownish red 

or often whitish due to dense pruina, the entire colony of 

squamules 1-10 cm diameter. Squamules middle-sized 

to large (~ 1 cm), round to irregular, rarely flat, more 

commonly conspicuously concave. Margin downturned, somewhat imbricate or crowded. Rhizines lacking. Apothecia common and 

black, flat to somewhat convex, small (up to 2 mm), borne on squamule margins. 

Spores 8 per ascus, single-celled, colorless, ellipsoid, 7-18 × 5-9 μm. Photobiont 

green (Myrmecia). 

Habitat: On soils in arid mid-elevation sites, particularly in the Sonoran and Chihuahuan deserts. Often on calcareous soils.

Chemistry: C-, K+ red, KC-, P+ yellow.

Comments: Psora crenata is an especially common component of biological soil 

crusts in the ecotone between the Colorado Plateau and Sonoran Deserts. It often 

co-occurs with P. icterica. Less concave specimens of P. crenata could be confused 

with P. cerebriformis which has flat to convex squamules and a hemispherical brainlike morphology. Psora decipiens is generally pink to red (not entirely 

covered in pruina) and has smaller, flat squamules and larger apothecia. The common name comes from the shape of the thallus which 

resembles fish scales.

turned somewhat imbricate

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Psora decipiens

Common names: Blushing scale, sockeye scale, whiteedged red scale, pink polka dot lichen

Synonym: Lecidea decipiens

Description: Thallus squamulose, pinkish orange to 

brick red, the entire colony of squamules about 0.5-2 

cm diameter, crowded or separate. Squamules more or 

less round to lobate, usually less than 5 mm diameter, 

pruinose. Margins distinctly white. Rhizines lacking. Apothecia marginal, black and 

convex, common, 0.7-2 mm diameter. Spores 8 per ascus, single-celled, colorless, 

ellipsoid, 7-18 × 5-9 μm. Photobiont green (Myrmecia).

Habitat: On calcareous soils, especially gypsiferous soils.

Chemistry: All spot tests negative.

Comments: Psora decipiens is abundant on calcareous soils, occurring alongside 

such species as Placidium lachneum, Toninia sedifolia, Collema tenax, C. coccophorum, and Fulgensia desertorum. Psora tuckermanii is similar in size and growth 

form but has apothecia that are laminal and reddish brown rather than black. If the 

squamules are very dimple-shaped with a depression in the middle then it may be 

Psora crenata, and if the group of squamules are clustered and rounded in a brainlike shape it may be P. cerebriformis. All three of these species are 

occasionally white-looking from a 

heavy calcareous covering of pruinose crystals.

othecia marginal black and

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Psora icterica

Common names: Yellow scale, fishscale lichen

Synonym: Lecidea icterica

Description: Thallus squamulose, bright yellow to 

green-yellow to sulfur green, greener when moist. 

Upper surface dull, fissures present or lacking, with or 

without pruina. Pruina can give the thallus a white color 

or cast when dry. Squamules attached to the substrate 

with lobate margins somewhat upturned, scattered to contiguous. Rhizines lacking. 

Apothecia common, hemispherical, dark brown to black, epruinose, variable in size. 

The upturned margins can appear slightly lighter in color. Spores 8 per ascus, singlecelled, colorless, ellipsoid, 7-18 × 5-9 μm. Photobiont green (Myrmecia).

Habitat: On soils in arid regions.

Chemistry: C-, K-, KC-, P-, UV+ dull orange (rhizocarpic acid).

Comments: Psora icterica’s yellowish green to sulfur green color distinguishes it 

from almost all other lichens in these warm desert regions. The squamules can be 

dense or sparse and are more spread out than many other Psora species. It could be 

confused with Acarospora schleicheri, but it has small hemispherical apothecia in 

contrast with the larger, flat, immersed apothecia of A. schleicheri, which also has a 

more sulfur yellow-green thallus. Acarospora schleicheri has a more 

northerly distribution than P. icterica and co-occurs with Cladonia

species.

with lobate margins somewh

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Psora montana

Common name: Little brown-eyed scale

Synonym: None

Description: Thallus small, squamulose, medium brown 

to dark reddish brown, dull to somewhat shiny, epruinose or more rarely somewhat pruinose. Squamules 

0.5-2 mm diameter, elongated, attached to the substrate 

or partly curving up, contiguous or irregularly imbricate. 

Margins the same color as the upper surface or somewhat paler, usually straight, 

deeply incised to lobate. Lower surface pale brown to medium brown. Rhizines 

lacking. Apothecia laminal, usually weakly to moderately convex, up to 1.2 mm 

diameter. Apothecia can be nearly half the size of the squamules and are mounded 

upon the squamule, protruding. Spores 8 per ascus, single-celled, colorless, 9-14 × 

5-7 μm. Photobiont green (Myrmecia).

Habitat: On soils or in rock crevices, as well as in rock crevices in alpine areas, 

common in the Great Basin and Columbia Basin.

Chemistry: Medulla C+ reddish or C-, KC+ reddish or KC- (gyrophoric acid); 

squamules C+ red or KC+ red. However, this reaction is unreliable and TLC is 

needed to confidently distinguish between P. montana and P. globifera.

Comments: Psora montana has squamules smaller than many other 

Psora species. Psora montana is similar to P. pacifica but with closely 

attached squamules and almost black 

apothecia. 

t paler usually straight

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Psora tuckermanii

Common name: Brown-eyed scale

Synonym: None

Description: Thallus squamulose, pale yellowish brown 

to almost chocolate brown with frosty, white, pruinose 

margins. Squamules smooth and somewhat shiny, 

scale-like, mostly crowded, overlapping, medium-sized. 

The entire colony can be 10-25 cm. Rhizines lacking. 

Apothecia laminal or marginal, round, mostly reddish brown, and up to 2.5 mm 

wide. Spores 8 per ascus, single-celled, colorless, ovoid-ellipsoid, 9-14 × 5-6.5 μm. 

Photobiont green (Myrmecia).

Habitat: On soils and soil over rock, common in cold deserts.

Chemistry: All spot tests negative.

Comments: Slicing into the apothecia to observe the color will help distinguish this 

from Psora decipiens which has black apothecia. Psora tuckermannii has pruinose 

margins that distinguishes it from P. globifera. Psora tuckermannii is similar to P. 

pacifica but with more closely attached squamules and almost 

black apothecia. Psora tuckermanii is endemic to North 

America and is named after Tuckerman, who was an early 

North American lichenologist based at Harvard 

University.

Apothecia laminal or margin

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Squamarina lentigera

Common names: White rim lichen, rim lichen

Synonym: Lecanora lentigera

Description: Thallus squamulose with slightly foliose 

lobe margins, generally appearing whitish green due to 

white pruina over a yellowish green cortex. Squamules 

form distinct rosettes attached to the substrate, about 3-6 

cm diameter (occasionally much larger). Thallus margin 

distinctly lobate. Lower surface pale, rarely darkening, with rather few and inconspicuous rhizines. Apothecia are common, lecanorine, rimmed and tan-colored, up 

to 4 mm diameter. Spores 8 per ascus, single-celled, colorless, ellipsoid, thin-walled, 

12-14 × 4-5 μm. Photobiont green, chlorococcoid, unicellular. 

Habitat: On calcareous and especially gypsiferous soils in arid regions.

Chemistry: C-, K+ pale yellow or red, KC+ yellow, P-.

Comments: Common, but generally not abundant on gypsum-containing soils, 

especially in the Colorado Plateau region where it can be very foliose and is easily 

separated from substrate. May occasionally form impressively large populations 

covering up to a square meter. It is found along with Psora decipiens, Fulgensia

bracteata, Diploschistes diacapsis, and an unusually diverse gypsum soil crust flora. 

Although it occurs with several other whitish lichens, it is easily distinguished by its more foliose growth 

form, whitish green thallus, and tan 

apothecia. 

with rather few and incon

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Texosporium sancti-jacobi

Common name: Woven-spore lichen

Synonym: Cyphelium sancti-jacobi

Description: Thallus crustose, thin, whitish to pale grayish, pruinose. Patches of thalli with clusters of apothecia 

range in size from 0.3 to 3 cm diameter. Apothecia are 

circular, 0.5-1.5 mm diameter, with a lecanorine margin 

concolorous with the thallus. The centers of the apothecia are filled with a characteristic dark, powdery, spore mass ranging from blackish 

to olive green in color and often tinged with bright yellow at the rim. Spores 8 

per ascus, 2-celled (which will be apparent only in the immature spores found at 

the base of the apothecium), black, 19-26 × 10-14 μm. As the spores mature, they 

become tightly wrapped with fungal hyphae that become progressively darker and 

thicker, thus obscuring the spore structure. Photobiont green, chlorococcoid.

Habitat: Rare and inconspicuous, on organic matter and organic soils.

Chemistry: All spot tests negative.

Comments: The coloration of the yellow rim, in contrast to the olive-green to black 

apothecia, is diagnostic. This lichen is uncommon and is an old growth sagebrush 

habitat indicator. It needs well decomposed organic 

matter as a substrate and is vulnerable 

to trampling.

ecia are filled with a charact

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Thrombium epigaeum

Common name: Thrombium lichen

Synonym: None

Description: Thallus crustose, often finely granulose, 

grayish, greenish, or yellowish green to brownish, 

effuse, film-like, smooth, slightly uneven or disappearing at maturity. Upper surface subgelatinous when wet. 

Epruinose. Perithecia almost globose, fully immersed 

with only the ostioles showing as black dots, up to 0.45 mm diameter. Exciple 

brown, 250-400 μm diameter. Spores 8 per ascus, single-celled, colorless, 15-30 × 

5-12 μm. Photobiont green, chlorococcoid (Leptosira).

Habitat: An ephemeral early colonizer of more or less calciferous, clayey soils, 

often in rather disturbed habitats.

Chemistry: All spot tests negative.

Comments: This species is easily overlooked and under-collected. It can be common on mineral soils low in organic matter and is difficult to collect. It is very fragile and, if not properly processed, will break apart and become piles of unidentifiable 

soil. This early ephemeral colonizer can stabilize soil for further colonization by 

other species. It is widespread and most easily recognized when moist. The surface 

of this lichen can be green or white 

when dry. One has to look closely to 

see the black perithecia.

mm diameter Exciple

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Toninia ruginosa

Common name: Black and bruised lichen

Synonym: Toninia caeruleonigricans

Description: Thallus squamulose, greenish to yellowish brown or bluish to almost black. Squamules round, 

swollen, more or less crowded, wavy, rough, folded, up 

to 5 mm diameter. Rhizines lacking. Apothecia 0.2-3 

mm across. Disks dull black to jet black, flat to slightly 

convex. Exciple thick, black, becoming curved, finally disappearing. Spores 1- to 

8-celled, needle-shaped, about 2-3 × 16-23 μm. Photobiont green, chlorococcoid.

Habitat: On soils and rock in open habitats and woodlands, often on calcareous 

soils. 

Chemistry: All spot tests negative on the thallus.

Comments: Most Toninia species become established on other lichen thalli as weak 

parasites before becoming free-living, and some remain as parasites. The preferred 

hosts are generally cyanobacterial lichens such as Collema and Placynthium, but 

some common Toninia species such as T. ruginosa, grow on green algal lichens. 

They are often in lichen communities that include calcareous soils and rock lichens 

such as Endocarpon, Fulgensia, Placidium, and Peltula. Other species of Toninia

can be found on soils and soil on rock ledges. Unlike T. ruginosa, T. 

sedifolia is pruinose white. Both have 

K+ red to violet epithecia, while T. 

tristis has a K- epithecium.

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convex Exciple thick black

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Toninia sedifolia

Common names: Earth-wrinkles, blue blister lichen

Synonym: Toninia caeruleonigricans

Description: Thallus squamulose, upper surface bluish 

gray or grayish olive due to dense pruina. Squamules 

convex, ranging from round to irregular and folded, 

up to 3 mm diameter. Lower surface dark olive-green 

to dark grayish green underneath. Rhizines lacking. 

Apothecia lecideine, black and convex, borne between the squamules. Spores 8 per 

ascus, 2-celled, colorless, ellipsoid to needle-shaped. Photobiont green, chlorococcoid, unicellular.

Habitat: On calcareous soils and on limestone rocks and in limestone rock crevices.

Chemistry: All spot tests negative.

Comments: This species is common in the Colorado Plateau region and middle to 

upper elevations of the warm deserts; it is less common in the Great Basin, Great 

Plains, and Columbia Basin. It is commonly found with other lime-loving species 

such as Psora decipiens, P. cerebriformis, Collema coccophorum, and Placidium 

lachneum. Its convex squamules, bluish gray color, and hemispherical black 

apothecia make it fairly easy to identify. It could potentially be confused with some 

small-squamuled, highly pruinose Psora species, but most of these 

have flat squamules and are not bluish. Toninia ruginosa is not pruinose.

he squamules Spores 8 per

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Trapeliopsis glaucopholis

Common name: Coastal trapeliopsis

Synonyms: Trapeliopsis wallrothii, T. californica

Description: Thallus thick squamulose, white, cream, 

pale gray to medium gray, slightly to distinctly glossy, 

forming colonies up to 10 cm or more diameter, 

epruinose. Squamules usually convex, contiguous to imbricate, edges of squamules appressed or free, 1-4 mm 

diameter, edge often weakly dissected into lobes about 1 mm wide. Lower surface 

tan to white, corticate where free. Rhizines lacking. Apothecia common, dull black, 

gray-black, grayish, pinkish brown or variegated with those colors, up to 2(6) mm 

diameter, often dividing into compound apothecia. Margin lecideine. Spores 8 per 

ascus, single-celled, 5.5-8.0 × 3-4 μm. Photobiont green, chlorococcoid. 

Habitat: Usually on soils and mosses over rock in relatively dry habitats. 

Chemistry: Thallus C+ red, K-, KC+ red, P-, UV-.

Comments: Trapeliopsis steppica is distinguished from T. glaucopholis by the presence of dark granular soredia in discrete roundish soralia, a thinner duller cortex, and 

slightly smaller and more appressed squamules. The upper cortex of T. glaucopholis

averages about twice as thick as the cortex in T. steppica. Trapeliopsis wallrothii is a 

European species and the name has been misapplied in North America. 

It has flatter squamules which are often nearly areolate with coarse 

thalloid granules and larger spores. 

diameter edge often weakly

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Trapeliopsis granulosa

Common name: Mottled-disk trapeliopsis

Synonyms: Lecidea grandulosa, L. quadricolor

Description: Thallus pale green, gray, white to sometimes brownish, thin to granular and breaking into 

patchy soredia, or at least with a rough and wart-like 

texture. Soredia whitish to yellow-brown in color. 

Apothecia round to wavy with a constricted base, pale 

pinkish brown to dark brown. Spores 9-13 × 4-6 μm. Photobiont green (Trebouxia). 

Habitat: On organic matter and dead plant parts. Widespread and common, occurring in all habitat types, but more frequent in cooler and montane areas. This species 

is very widespread and can cover large areas among the trees in dry woodlands 

(pinyon and ponderosa pine), and prefers acidic soils or organic matter but can also 

be found on bare soils and charred wood.

Chemistry: C+ pink, K-, KC+ red, P-.

Comments: Because this species is an important early colonizer of bare soils, 

organic mulch, or decomposed wood, forest managers in Quebec have disseminated 

this lichen over tracts of recently burned forest. The whitish thallus reflects sunlight, 

cooling the surface and allowing it to accumulate more moisture. The lichen itself 

helps to prevent erosion (Brodo et 

al. 2001). 

otobiont green (Trebouxia)

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Trapeliopsis steppica

Common name: Inland trapeliopsis

Synonym: Trapeliopsis wallrothii

Description: Thallus squamulose, cream to light gray or 

more often medium gray, dull, occasionally appearing 

somewhat pruinose. Squamules contiguous to imbricate, 

roundish to elongate, 0.15-0.50 mm thick and 0.5-1.5 

mm long, appressed, marginally downrolled or ascending. Soredia usually present, dark gray to black or greenish black, in discrete, roundish soralia that are slightly concave to convex. Rhizines lacking. Apothecia rare, 

sessile, pinkish brown to almost black. Spores 8 per ascus, single-celled, colorless, 

ellipsoid, 18-28 × 8-18 μm. Photobiont green, chlorococcoid (possibly Chlorella or 

Pseudochlorella). 

Habitat: On soils, soil over rock, or moss over rock in grassland and shrub steppes, 

generally in areas little disturbed by grazing.

Chemistry: Thallus C+ red, K-, KC+ red, P-, UV-.

Comments: Trapeliopsis steppica is differentiated from T. glaucopholis by the presence of dark granular soredia in discrete roundish soralia, a thinner duller cortex, and 

slightly smaller and more appressed squamules. Trapeliopsis steppica differs from 

T. bisorediata in having only dark soralia which tend to be marginal 

rather than central in the areolae. Trapeliopsis steppica is also somewhat darker gray in color, less pruinose, and more squamulose. This 

lichen is a good indicator of old growth arid habitats.

ing Soredia usually present

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Xanthoparmelia chlorochroa

Common name: Tumbleweed shield lichen

Synonyms: Parmelia chlorochroa, P. molliuscula

Description: Thallus foliose and vagrant, yellowish 

green, forming rounded cushions of dichotomously 

branched lobes, epruinose. Lobes somewhat flattened 

(dorsiventral) to in-rolled, generally 1-5 mm wide, with 

margins strongly curled inward, almost forming tubes. 

Lower surface pale to dark brown, strongly convex but not completely in-rolled, often with raised rim toward apices, moderately to densely rhizinate, closely or loosely 

appressed or unattached. Rhizines concolorous with lower surface. Apothecia rare, 

lecanorine, with broad brown disks and thallus-colored margins. Spores 8 per ascus, 

single-celled, colorless, ellipsoid, 6-13 × 4-8 μm. Photobiont green (Trebouxia).

Habitat: On mineral soils and rock. Most species are found in open, relatively dry 

sites. Vagrant on desert and steppe soils.

Chemistry: Medulla C-, K+ red, KC-, P+ orange.

Comments: Some lobate species of Lecanora, such as L. muralis and L. novomexicana, can also resemble Xanthoparmelia. Xanthoparmelia neochlorochroa has a 

different chemistry and a black lower surface, and X. norchlorochroa has a dull 

black lower surface lacking rhizines and with pronounced reticulate 

ridges and veins. This species is a common food for wild and domestic 

ungulates. See next page for other 

species of Xanthoparmelia. 

ot completely in rolled of

90

500

1,500

1,000

2,000

2,500

3,000

3,500

4,000

Elevation

Meters
91

Table of the common soil-occurring Xanthoparmelia species.

Species Morphology Chemistry Habitat

camtschadalis 

(ND)

Upper surface 

with small lightcolored spots 

(maculate), 

rhizines

Cortex K-, KC+ yellow, 

medulla K+ yellow 

becoming reddish orange 

or orangish red, P+ 

yellowish or

orangish (salazinic acid)

Shrub steppe/

badlands

chlorochroa Broad lobes, 

rhizines

Medulla K+ red, KC-, 

C- (salazinic acid), and P+ 

orange

Grasslands

neochlorochroa 

(ND)

Rhizines, broad 

lobes

Medulla K+ yellow to red 

(norstictic acid)

Calcareous 

rangelands

norchlorochroa 

(ND) No rhizines

Medulla C-, K+ red, KC- 

(norstictic acid) and P+ 

orange

Calcareous 

badlands

wyomingica 

(ND)

Narrow lobes, 

rhizines

Cortex KC+ yellow, 

medulla K+ yellow turning 

red, P+ orangish (salazinic 

acid) 

Rocky 

windswept 

sites

X. camtschadalis

X. norchlorochroa

X. wyomingica wyomingica

X. neochlorochroa X neochlorochroa
92

Species Authority

Acarospora nodulosa var. nodulosa (Dufour) Hue.

Acarospora schleicheri (Ach.) A. Massal.

Aspicilia aspera (Mereschk.) Tomin

Aspicilia desertorum form terrestris Tomin (Tomin)

Aspicilia filiformis Rosentr.

Aspicilia fruticulosa (Eversm.) Flagey

Aspicilia hispida Mereschk.

Aspicilia mastrucata (Wahlenb.) Th. Fr.

Aspicilia reptans (Looman) Wetmore

Athalmia hyalina (Somm.) Hatt.

Bryum argenteum Hedw.

Bryum caespiticium Hedw.

Buellia elegans Poelt

Buellia punctata (Hoffm.) A. Massal.

Caloplaca tominii Savicz

Candelariella citrina de Lesd.

Cephaloziella divaricata (J. E. Smith) Schiffner or (Sm.) Schiffn

Ceratodon purpureus (Hedw.) Brid.

Cladonia fimbriata (L.) Fr.

Cladonia pocillum (Ach.) Grognot

Collema coccophorum Tuck.

Collema tenax (Sw.) Ach.

Didymodon vinealis (Brid.) Zand.

Diploschistes diacapsis (Ach.) Lumbsch.

Diploschistes muscorum (Scop.) R. Sant.

Encalypta vulgaris Hedw.

Endocarpon pusillum Hedw.

Fossombronia longiseta (Austin) Austin

Fulgensia bracteata (Hoffm.) Räsänen

Funaria hygrometrica Hedw. 

Heppia lutosa (Ach.) Nyl.

Leptochidium albociliatum (Desmaz.) M. Choisy

Appendix: Authorities
93

Species Authority

Leptogium lichenoides (L.) Zahlbr.

Massalongia carnosa (Dickson) Korber 

Megaspora verrucosa (Ach.) Hafellner & V.Wirth

Ochrolechia upsaliensis (L.) A. Massal.

Peltigera rufescens (Weis.) Mudd

Peltula richardsii (Herre) Wetmore.

Phaeorrhiza nimbosa (Fr.) H. Mayrh. & Poelt

Physconia muscigena (Ach.) Poelt 

Physconia perisidiosa (Erichsen) Moberg

Placidium lacinulatum (Ach.) Breuss 

Placidium squamulosum (Ach.) Breuss

Psora cerebriformis Weber

Psora crenata (Taylor) Reinke

Psora decipiens (Hedwig) Hoffm.

Psora icterica (Mont.) Mull. Arg.

Psora montana Timdal

Psora tuckermanii R. Anderson ex Timdal 

Pterygoneurum ovatum (Hedw.) Dix.

Squamarina lentigera (Weber) Poelt

Syntrichia caninervis Mitt.

Syntrichia ruralis (Hedw.) Web. & Mohr

Texosporium sancti-jacobi (Tuck.) Nadv.

Thrombium epigaeum (Pers.) Wallr.

Toninia ruginosa (Tuck.) Herre 

Toninia sedifolia (Scop.) Timdal

Tortula inermis (Brid.) Mont.

Trapeliopsis glaucopholis (Nyl. ex Hasse) Printzen & McCune

Trapeliopsis granulosa (Hoffm.) Lumbsch.

Trapeliopsis steppica McCune & Camacho

Xanthoparmelia camtschadalis (Ach.) Hale

Xanthoparmelia chlorochroa (Tuck.) Hale

Xanthoparmelia neochlorochroa Hale

Xanthoparmelia norchlorochroa Hale

Xanthoparmelia wyomingica (Gyeln.) Hale
94

Glossary

Acuminate: Gradually narrowing to a point, like a spade on a playing card

Adnate: Tightly adherent to surface

Alga (Algae): A simple plant composed of a single cell or a string of cells

Apothecium (Apothecia): A disk- or cup-shaped spore-producing organ

Appressed: Lying flat or pressed closely against the substrate

Areolate: Sharply divided into tile-like areolae

Areole (Areolae): A small, irregular, often angular patch of thallus delimited by cracks or 

chinks in the thallus surface

Ascus (Asci): The sac-like structure in which the spores are formed

Awn: Bristle or hair at a moss leaf tip, sometimes colored

Bryophyte: Member of phylum Bryophyta; refers collectively to mosses, liverworts and 

hornworts

Calyptra (Calyptrae): A thin hood covering the lid of the moss sporophyte capsule, usually falling at maturity

Capsule: Inflated structure at the end of the moss sporophyte containing spores

Chemical (or physical) crust: Inorganic crust caused by features such as platy soil surface particles or an accumulation of salts

Concolorous: Of the same color throughout

Cortex: The outermost layer of the thallus, which, if present, consists of hyphae which 

may appear either cellular or fibrous

Crenate: With a scalloped or round-toothed edge

Crustose: Crust-like lichens that are closely attached to their substrate and lack a lower 

cortex

Cucullate: Hood-shaped

Cyanobacteria: Simple photosynthesizing organisms that can fix atmospheric nitrogen 

and serve as a photobiont in lichen associations (also called blue-green algae)

Cyphella (Cyphellae): A pore recessed into the lower thallus surface where medullary 

hyphae protrude

Disk: The upper surface of a lichen apothecium enclosed by, but not including, the margin

Dioecious: Having male and female reproductive organs on separate plants

Dorsiventral: Flattened, with upper and lower surfaces

Ecotone: A transitional zone between two adjacent and distinct ecosystems.

Entire: Without teeth; more or less smooth on the margin

Epithecium (Epithecia): The uppermost portion of the hymenium formed by the tips of 
95

the paraphyses, which are frequently expanded or branched, often pigmented and sometimes containing tiny granules

Epruinose: Lacking pruina

Exciple: The margin around the apothecial disk

Excurrent: Refers to a leaf mid-rib that runs out beyond the lamina of the leaf

Foliose: Having leaf-like lobes with distinct upper and lower surfaces

Fruticose: A shrubby or hair-like growth form attached only at the base or free growing 

and normally with no clearly distinguishable upper and lower surfaces

Gemma (Gemmae): Small asexual reproductive structure that detaches from the parent 

and develops into a new individual

Globose: Globe-shaped 

Hymenia (Hymenium): The spore-bearing layer of fungal reproductive structures (ascoma)

Hypha (Hyphae): Fungal filaments, often modified and resembling round or angular cells

Hypothallus: The first and purely fungal (without photobiont) layer upon which an algaecontaining thallus may develop, sometimes appearing as radiating, branched hyphae or 

hyphal bundles, often projecting beyond the thallus onto substrate

Hypothecium (Hypothecia): The tissue just below the hymenium (and subhymenium) but 

above the exciple, often with a distinctive color or texture but sometimes merging with the 

exciple

Imbricate: With overlapping layers

Immersed: Embedded in the substratum

Isidium (Isidia): Small, asexual reproductive structures on lichens that are minute and 

finger-like, covered with a cortex and contain the photobiont

Isidiod: Resembling isidia

Isidiate: Having isidia

Lamina (Laminae): The flattened, generally green, part of the leaf

Laminal: In the middle, or main part, of the thallus surface, rather than on the margins

Lecanorine: An apothecial margin which usually contains a photobiont and often resembles the thallus, but not the disk, in color and texture

Lecideine: An apothecial margin with no photobiont cells that often resembles the disk, 

but not the thallus, in color and texture

Lichen: Composite organism made up of a fungus and an alga, a cyanobacterium, or all 

three

Lid: Operculum; top part of moss capsule that comes off to release spores

Liverwort: A bryophyte belonging to the class Hepaticae, with flattened bodies that have 

distinct upper and lower surfaces
96

Lobate: Bearing lobes

Lobe: A flattened branch or projection

Lobulate: Having lobules

Lobule: Tiny, lobe-like, dorsiventral asexual reproductive outgrowths

Maculate: Spotted or blotched 

Margin: Referring either to the outer edge of foliose or crustose lichen thalli or the outer 

boundary of apothecia

Medulla: Whitish (rarely orange or yellow) internal layer of most lichens, generally composed of loosely packed fungal hyphae

Mesic: Characterized by moist conditions, neither very wet nor very dry.

Monoecious: Having male and female reproductive organs on the same plant

Moss: Non-vascular plant in the division Bryophyta which has leaves attached in a whorl 

about the stem and long-lasting sporophyte with spores that ripen after elongation of the 

seta

Neck: The sterile basal portion of the capsule between the spore sac and the summit of the 

seta, often narrowed

Oblong: Proportioned about 1:3-6 with the margins more or less parallel; rectangular but 

ends not necessarily squared off

Ovate: Egg-shaped with the larger end at the base

Obovate: Inversely ovate, with the narrower end at the base

Ostiole: A small opening or pore

Papilla (Papillae): Minute protuberance on the surface of a cell

Papillose: Having papillae

Paraphysis (Paraphyses): A sterile filament (sometimes branched, attached at the base 

and free at the summit) found in amongst the asci in the hymenium

Patent: Spreading from the stem at an angle of 45° or more

Percurrent: Extending to the apex of a leaf

Perianth: Sterile tubelike tissue that surrounds the sporophyte 

Peristome: The fringe of teeth surrounding the mouth of the capsule, becoming exposed 

after the lid falls

Perithecium (Perithecia): A globose or flask-shaped fruiting body (ascoma) completely 

enclosed with protective sterile tissue and with an opening pore at the tip

Photobiont: The photosynthetic component in a lichen, either algae in the strict sense 

(e.g., green algae) or cyanobacteria (blue-green algae), or both

Podetium (Podetia): The upright, hollow stalk formed by an elongated apothecium

Pruina: Powdery frost-like deposit, typically composed of calcium oxalate
97

Pruinose: Having a frosted appearance caused by a deposit of pruina

Pseudocyphella (Pseudocyphellae): A break or opening in the cortex where medullary 

hyphae protrude; it may be round, irregular, angular, or a minuscule pore

Pycnidium (Pycnidia): Minute, flask-shaped, fungal fruiting body

Recurved: Curved downward or backward

Rhizine: Root-like hyphae on the lower side of a foliose lichen thallus

Rhizoid: Root-like structure on the lower side of a moss

Rosette: A flower-like pattern arrayed around a common point of attachment

Sessile: Attached directly to the thallus surface without a stalk of any kind

Seta (Setae): The stalk of a moss sporophyte which supports the capsule 

Simple: Not divided; unbranched

Soralium (Soralia): An area of the thallus in which the cortex has broken down or 

cracked and soredia are produced

Soredium (Soredia): Asexual reproductive structure that is powdery to granular, not covered with a well-defined cortex, and contains both algal (photobiont) and fungal (mycobiont) components

Sorediate: Having soredia

Spores: Microscopic reproductive bodies released from the sporophyte capsule of a moss 

or liverwort, or from the apothecia of a lichen

Sporophyte: Spore-producing plant structure or phase of a moss or liverwort, consisting 

of a foot, a seta, and a capsule, but not leaves or rhizoids

Spot test: Tests for color reactions obtained by applying a liquid chemical reagent to a 

lichen

Squamule: Small flakes or scales of a lichen, lifting from the substrate, at least at the 

edges, often rounded, ear-like, or lobed

Squamulose: Composed of or characterized by having squamules—an intermediate 

growth form between crustose and foliose

Squarrose: Branching at right angles from a single main axis, like a bottlebrush

Sterile: Without sexual reproductive structures

Stratified: Differentiated into layers

Subfoliose: Almost foliose, pertaining to the overall growth form of a crustose thallus that 

has marginal lobes showing some tendency to curve upwards

Terete: Circular in cross-section—cylindrical and smooth

Thallus (Thalli): The vegetative body consisting of both algal and fungal components, not 

differentiated into a stem and leaves

TLC: Thin layer chromatography—a technique used to separate chemical compounds
98

Additional resources

Websites

Biological Soil Crusts

J. Belnap, U. S. Geological Survey

http://www.soilcrust.org/

Bryophyte Flora of North America

Missouri Botanical Garden

http://www.mobot.org/plantscience/

BFNA/bfnamenu.htm

Common Wildflowers, Lichens, and 

Mosses of the Shrub-steppe

Pacific Northwest National Laboratory

http://ecology.pnl.gov/Gallery/Wildfl.asp

Cyanosite: A Webserver for Cyanobacterial Research 

M. A. Schneegurt, Purdue University

http://www-cyanosite.bio.purdue.edu/

eFloras

Missouri Botanical Garden

www.eFloras.org 

Field Guide to Selected Rare Plants 

of Washington

Washington State Department of 

Natural Resources 

http://www.dnr.wa.gov/nhp/refdesk/

fguide/htm/fgmain.htm

Internet Resources for Bryologists 

and Lichenologists

American Bryological and Lichenological Society 

https://mywebspace.wisc.edu/jpbennet/

web/abls/resources.html

Key to the Lichen Genera of the Pacific Northwest

B. McCune, Oregon State University

http://oregonstate.edu/~mccuneb/pnw.PDF

Lichen Herbarium

Arizona State University, School of Life 

Science

http://nhc.asu.edu/lichens/flora/publications.jsp

Lichens of North America

S. Sharnoff and S. Sharnoff, Stephen 

Sharnoff Photography

http://www.lichen.com

Mosses, Lichens, and Liverworts of 

the Northwoods 

E. J. S. Rook 

http://www.rook.org/earl/bwca/nature/moss

Mosses of Nevada

L. R. Stark and J. R. Shevock, Nevada 

Natural Heritage Program

http://heritage.nv.gov/mosses/index.htm

The Plants Database

Natural Resources Conservation Service 

http://plants.usda.gov

LIAS – A Global Information System 

for Lichenized and Non-Lichenized 

Ascomycetes

http://www.lias.net/

Botanische Staatssammlung München
99

Books and articles

Belnap, J., and O. L. Lange, editors. 2003. Biological Soil Crusts: Structure, Function, and 

Management, Second edition. Springer-Verlag, Berlin. 

Belnap, J., S. L. Phillips, D. L. Witwicki, and M. E. Miller. In press. Visually assessing cyanobacterial biomass and soil surface stability in cyanobacterially dominated biological 

soil crusts. Journal of Arid Environments.

Brodo, I. M., S. D. Sharnoff, and S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven, Connecticut.

Conard, H. S., P. L. Redfearn, J. F. Bamrick, and E. T. Cawley. 1979. How to Know the 

Mosses and Liverworts. W. C. Brown Co., Dubuque, Iowa. 

Corbridge, J. N., W. A. Weber, and K. C. Abbott. 1998. A Rocky Mountain Lichen Primer. 

University Press of Colorado, Niwot, Colorado.

Esslinger, T. L., and R. S. Egan. 1995. A sixth checklist of the lichen-forming, lichenicolous, and allied fungi of the continental United States and Canada. Bryologist 98: 

467-549. 

Fink, B. 1935. The Lichen Flora of the United States. University of Michigan Press, Ann 

Arbor, Michigan.

Flowers, S., and A. Holmgren, editors. 1973. Mosses: Utah and the West. Brigham Young 

University Press, Provo, Utah.

Goward, T., B. McCune, and D. Meidinger. 1994. The Lichens of British Columbia: Illustrated Keys. Part 1 - Foliose and Squamulose Species, Special Report Series No. 8. 

Crown Publications, Inc., Victoria, British Columbia.

Hale, M. E. 1990. A synopsis of the lichen genus Xanthoparmelia (Vainio) Hale (Ascomycotina, Parmeliaceae). Smithsonian Contributions to Botany 74:250.

Hale, M. E., J. Bamrick, E. T. Cawley, and W. G. Jaques. 1979. How to Know the Lichens. 

W. C. Brown Co., Dubuque, Iowa.

Hale Jr., M. E., and M. Cole. 1988. Lichens of California. University of California Press, 

Berkeley, California.

Herre, A. W. C. T. 1912. New or rare California lichens. Bryologist 15:81-87.

Howard, G. E. 1970. The lichen genus Ochrolechia in North America north of Mexico. 

Bryologist 73:93-130.

Hutten, M., K. Hutten, and A. Woodward. 2001. 101 Common Mosses, Liverworts & 

Lichens of the Olympic Peninsula. Government Printing Office, Washington, DC.

Long, D. G., G. P. Rothero, and J. A. Paton. 2003. Athalamia hyalina (Sommerf.) S. Hatt. 

in Scotland, new to the British Isles. Journal of Bryology 25:253-257.

MacVicar, S. M. 1926. Student Handbook of British Hepatics, Second edition. Sumfield 

and Day, Easbourne, London.

McCune, B., F. Camacho, and J. Ponzetti. 2002. Three new species of Trapeliopsis on soil 

in western North America. Bryologist 105:78-85.

McCune, B., and L. Geiser. 1997. Macrolichens of the Pacific Northwest. Oregon State 
100

University Press, Corvallis, Oregon.

McCune, B., and T. Goward. 1995. Macrolichens of Northern Rocky Mountains. Mad 

River Press, Inc., Eureka, California.

McCune, B., and R. Rosentreter. 1992. Texosporium sancti-jacobi, a rare western North 

American lichen. Bryologist 95:329-333.

McCune, B., and R. Rosentreter. 2007. Biotic Soil Crust Lichens of the Columbia Basin: 

Monographs in North American Lichenology. Volume 1. Northwest Lichenologists, 

Corvallis, Oregon.

Nash III, T. H., B. D. Ryan, C. Gries, and F. Bungartz, editors. 2002. Lichen Flora of the 

Greater Sonoran Desert Region. Volume 1. Lichens Unlimited, School of Life Sciences, 

Arizona State University, Tempe, Arizona. 

Nash III, T. H., B. D. Ryan, P. Diederich, C. Gries, and F. Bungartz, editors. 2004. Lichen 

Flora of the Greater Sonoran Desert Region. Volume 2. Lichens Unlimited, School of 

Life Sciences, Arizona State University, Tempe, Arizona.

Nimis, P. L. 1981. Caloplaca tominii new to North America. Bryologist 84:222-225.

Øvstedal, D. O., and R. I. Lewis Smith. 2001. Lichens of Antarctica and South Georgia: 

A guide to their identification and ecology. Cambridge University Press, Cambridge, 

Massachusettes.

Purvis, O. W., B. J. Coppins, D. L. Hawksworth, P. W. James, and D. M. Moore. 1992. 

The Lichen Flora of Great Britain and Ireland. Natural History Museum Publications, 

London, UK.

Rosentreter, R. 1993. Vagrant lichens in North America. Bryologist 96:333-338.

Rosentreter, R. 1998. Notes on the Aspicilia reptans complex, with descriptions of two 

new species. Pages 163-170 in M. G. Glenn, R. C. Harris, R. Dirig, and M. S. Cole, 

editors. Lichenographia Thomsoniana: North American Lichenology. Mycotaxon Ltd., 

Ithaca, New York.

Sharp, A. J., H. Crum, and P. M. Eckel, editors. 1994. Moss Flora of Mexico. Memoirs of 

The New York Botanical Garden. Volume 69. New York Botanical Garden, New York.

Shic, H. W. 1986. The family Cephaloziellaceae in North America west of the hundredth 

meridian. Bryologist 89:155-162.

St. Clair, L. L. 1999. A Color Guidebook to Common Rocky Mountain Lichens. M. L. 

Bean Life Science Museum, Brigham Young University, Provo, Utah.

Thomson, J. W. 1987. The lichen genera Catapyrenium and Placidiopsis in North America. 

Bryologist 90:27-39.

Thomson, J. W. 1989. Additions and a revised key to Catapyrenium in North America. 

Bryologist 92:190-193.

Timdal, E. 1986. A revision of Psora (Lecideaceae) in North America. Bryologist 

89:253-275.

Wetmore, C. M. 1968. Lichens of the Black Hills of South Dakota and Wyoming: Biological Series No. 3. Michigan State University, Lansing, Michigan.

Wetmore, C. M. 1970. The lichen family Heppiaceae in North America. Annals of the Missouri Botanical Garden 57:158-209.
101

Acarospora

nodulosa var. nodulosa 33, 

34, 40, 92

nodulosa var. reagens 40

schleicheri 31, 41, 58, 

79, 92

species 52

Agrestia

hispida 46

Amandinea

punctata 50

Androcryphia

longiseta 28

Anomobryum

lanatum 14

Aspicilia

aspera 33, 42, 43, 92

californica 44, 48

desertorum form terrestris 

34, 42, 43, 92

filiformis 34, 42, 43, 44, 

48, 92

fruticulosa 33, 42, 45, 

46, 92

hispida 6, 34, 42, 45, 46, 

92

mastrucata 30, 47, 48, 92

reptans 34, 42, 43, 44, 

48, 92

species 66

Athalamia

hyalina 25, 26, 92

Barbula

caninervis 22

cavifolia 21

chrysochaete 18

constricta 18

elbertii 18

fusia 18

leuhmannii 18

pachydictyon 18

rectifolia 18

ruralis 23

saussuriana 16

squamifera 17

subcontorta 18

subtorquata 18

torquata 18

validinervia 16

vinealis 18

Bracythecium

species 68

Bryum

arenicola 15

argenteum 6, 11, 14, 20, 

22, 92

argentum 14

caespiticium 12, 15, 16, 

23, 92

extinctorium 19

kunzei 12, 15, 22

symblepharum 15

Buellia

elegans 33, 34, 49, 50, 92

papillata 30

punctata 30, 50, 92

punctiformis 50

species 6

Caloplaca

bracteata 60

species 60

tominii 31, 51, 92

Candelariella

citrina 31, 52, 9

species 51, 52, 60

terrigena 52

Catapyrenium

lacinulatum 73

species 59

squamulosum 74

Cephaloziella

byssacea 27

confervoides 27

divaricata 25, 27, 92

rubella 27

starkei 27

Ceratodon

antarcticus 16

grossiretis 16

minutifolius 16

purpureus 11, 15, 16, 20, 

23, 68, 92

validus 16

Cladonia

chlorophaea 53, 58

fimbriata 33, 53, 58, 92

major 53

pocillum 33, 53, 54, 92

pyxidata var. pocillum 54

species 35, 58, 68, 79

Clevea

hyalina 26

Collema

coccophorum 32, 55, 56, 

76, 78, 86, 92

cristatellum 56

dubium 55

novomexicanum 55

pulposum 56

species 6, 64, 85

tenax 32, 55, 56, 73, 76, 

78, 92

Crossidium

aberrans 17

crassinerve 17

desertorum 17

erosum 17

seriatum 17

spatulaefolium 17

species 12, 17

squamiferum 17

succulentum 17

Cyphelium

sancti-jacob 83

Dermatocarpon

hepaticum 73, 74

Didymodon

Index
102

australasiae 18

insularis 18

trifarius 18

vinealis 11, 18, 92

Diploschistes

albissimus 57

canadensis 58

diacapsis 33, 40, 57, 58, 

82, 92

muscorum 33, 41, 57, 

58, 92

scuposus 41

species 43, 66

Encalypta

australis 19

extinctoria 19

novae-seelandiae 19

orsinii 19

pumila 19

rhaptocarpa 19

species 11, 12, 24

tasmanica 19

vulgaris 11, 12, 19, 92

Endocarpon

pusillum 35, 59, 92

schaereri 59

species 85

Fossombronia

kashyapii 28

longiseta 25, 28, 92

vermiculata 28

Fulgensia

bracteata 31, 40, 57, 60, 

82, 92

desertorum 31, 60, 78

species 41, 60, 76, 85

Funaria

hygrometrica 11, 20, 92

Grimmia

species 18

Gymnostonum

pulvinatum 21

Heppia

conchiloba 37

lutosa 37, 61, 92

richardsii 69

species 69

Hymenostoma

encalyptroides 19

Lecanora

desertorum 43

fruticulosa 45

gypsicola 40

lentigera 82

mastrucata 47

muralis 90

nodulosa 41

novomexicana 90

reagens 41

reptans 48

species 90

terrestrialis 43

verrucosa 66

Lecidea

cerebriformis 76

coroniformis 77

crenata 77

decipiens 78

grandulosa 88

icterica 79

quadricolor 88

species 49, 75

Lecideaceae

species 49

Lecidella

species 49

Lepraria

species 32, 62

zonata 62

Leptochidium

albociliatum 32, 63, 92

species 63

Leptogium

albociliatum 63

burnetiae 63

lichenoides 32, 64, 93

pilosellum 63

saturninum 63

species 63, 64

Leskeela

cuspidate 16

Massalongia

carnosa 34, 65, 93

Meesia

kenyae 16

Megaspora

verrucosa 30, 48, 66, 93

Microcoleus

vaginatus 5

Nostoc

commune 5

Ochrolechia

species 62

upsaliensis 30, 67, 93

Pachyospora

verrucosa 66

Pannaria

carnosa 65

Parmelia

chlorochroa 90

farrea 72

molliuscula 90

Peltigera

canina 68

canina var. rufescens 68

kristinsonii 68

rufescens 34, 68, 93

species 6

Peltula

patellata 69

richardsii 37, 61, 69, 93

species 85

Pertusaria

species 62

Phaeorrhiza

nimbosa 37, 38, 70, 93

sareptana 37, 38, 70

species 70

Physcia

muscigena 71

Physconia

detersa 72
103

enteroxantha 34, 72

farrea 72

grisea 72

isidiigera 72

leucoleiptes 72

muscigena 30, 71, 93

perisidiosa 30, 34, 72, 93

Placidium

lachneum 35, 73, 78, 86

lacinulatum 35, 73, 74, 93

species 6, 55, 59, 61, 69, 

73, 74, 85

squamulosum 35, 73, 74, 

93

Placynthiella

imcalea 75

nigrum 75

oligotropha 75

species 31, 75

uliginosa 75

Placynthium

nigrum 75

species 85

Plagiochasma

erythrospermum 26

Pleopsidium

species 52

Polychidium

albociliatum 63

Polytrichum

species 23

Pottia

pilifera 21

Pseodocrossidium

crinitum 17

Psora

cerebriformis 36, 38, 40, 

76, 77, 78, 86, 93

crenata 36, 76, 77, 78, 93

decipiens 31, 36, 40, 55, 

57, 60, 76, 77, 78, 81, 

82, 86, 93

globifera 38, 80, 81

himalayana 36

icterica 31, 35, 77, 79, 93

montana 38, 80, 93

nipponica 36

pacifica 80, 81

species 6, 69, 79, 86

tuckermanii 36, 37, 78, 

81, 93

upsaliensis 67

Pterygoneurum

ovatum 6, 21, 93

species 11, 17

subsessile 12, 21

Rhizocarpon

species 49

Rhizoplaca

species 46

Riccia

species 26

Rinodina

nimbosa 70

phaeocarpa 70

Saccomorpha

species 75

Scytonema

myochrous 6

Solorinaria

despreauxii 61

Squamarina

lentigera 35, 57, 82, 93

Staurothele

species 59

Stegonia

mouretii var. crinita 21

Syntrichia

caninervis 13, 14, 21, 22, 

23, 93

princeps 23

ruralis 6, 12, 14, 15, 16, 

19, 22, 23, 68, 93

species 18, 24

subulata 24

Texosporium

sancti-jacobi 32, 83, 93

Thrombium

epigaeum 32, 84, 93

Toninia

caeruleonigricans 86

caeruleonigricome 85

ruginosa 37, 85, 86, 93

sedifolia 37, 76, 78, 85, 

86, 93

tristis 85

Tortula (see Syntrichia)

bistratosa 22

caninervis 22

crassinervia 17

desertorum 22

inermis 11, 19, 22, 23, 

24, 93

insulana 18

longimucronata 23

mairei 19

ruralis 23

saussuriana 16

squamifera 17

Trapeliopsis

bisorediata 89

californica 87

glaucopholis 36, 87, 89, 93

granulosa 30, 88, 93

species 6

steppica 35, 87, 89, 93

wallrothii 87, 89

Tremella

lichenoides 64

Urceolaria

albissima 57

Xanthoparmelia

camtschadalis 91, 93

chlorochroa 34, 90, 91, 93

neochlorochroa 90, 91, 93

norchlorochroa 91, 93

species 46

wyomingica 91, 93
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