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| ##                                                                    |
|  slender-spiked mannagrass {#slender-spiked-mannagrass .Title-Header} |
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| *Glyceria leptostachya* Buckl.                                        |
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| Plant Symbol = GLLE2                                                  |
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USDA NRCS Plant Materials Center, Corvallis, Oregon

##### Alternate Names {#alternate-names .Header-3}

##### Other common names include davy mannagrass, slimheaded mannagrass, and soft mannagrass. 

##### Uses {#uses .Header-3}

Slender-spiked mannagrass is a lesser known, mid-sized native grass
suitable for wetland restoration and enhancement. It may also be used
for seeding the edges of streams and lakes, as well as the bottom of low
gradient drainage ditches and other watercourses. This species exhibits
a low-lying growth form and vegetative spread that helps reduce erosion.
The prostrate floating leaves and stems may further aid in control
erosion by lining the banks of streams, waterways, and channels during
high flows. The seed and leaves are a likely source of food for
waterfowl, shore birds, songbirds, and small mammals, similar to other
mannagrasses.

Forage value and palatability for livestock are unknown. However, the
tender, green foliage is probably utilized by deer and other ungulates.

##### Status {#status .Header-3}

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status (e.g. threatened or endangered
species, state noxious status, and wetland indicator
values).![](media/image3.jpeg){width="2.9659722222222222in"
height="4.034027777777778in"}

##### Description and Adaptation {#description-and-adaptation .Header-3}

Slender-spiked mannagrass is a short-lived, perennial, cool season grass
with succulent foliage and erect to low lying stems that are 60 to 110
cm tall. Reportedly, this grass also produces rhizomes (underground
stems), but individuals often retain a more bunchgrass appearance.
Plants may spread vegetatively from lower stems that root at nodes
(joints) in contact with the soil. The leaf blades are flat to rolled
slightly inward, 3 to 7 (10) mm wide, and rough on both sides. On land,
they develop mostly at the base of the plant but floating leaves can
form when plants are submerged. The flowerhead (panicle) is open, 20 to
40 cm long, with a few branches pressed close to the main axis.
Slender-spiked mannagrass occurs from Alaska south to California but not
further inland.

*Key to identification:* In the Pacific Northwest USA,

this species resembles a smaller version of western mannagrass
(*Glyceria occidentalis*), which is coarser, more open, and has much
larger seeds. It can also be confused with northern mannagrass
(*Glyceria borealis*) but the latter has a smooth leaf blade while the
upper blades of slender-spiked mannagrass are rough in texture. Consult
a botanical key to distinguish these species.

*Relative abundance in the wild:* Generally uncommon throughout its
natural range compared to other mannagrasses. Scattered plants are
occasionally found along small streams and in riparian wetlands or
marshy areas, especially in the Willamette Valley of Oregon and along
the Pacific Coast. Seed ripens in July or August. Retention within the
panicle is poor to fair at best. Wild collections rarely yield much seed
because populations are usually small and plants are widely scattered.

*Adaptation:* This species is well adapted to wet meadows, the margins
of streams, lakeshores, freshwater marshy areas, and other depressions
that stay moist in summer. It easily withstands year round inundation by
developing a floating leaf growth form. However, longevity may be
reduced. This species is found on acidic soils that are coarse to fine
textured. Tolerance to salinity, alkalinity, or high soil acidity is
unknown. Slender-spiked mannagrass typically grows in full sun.

##### Establishment {#establishment .Header-3}

Slender-spiked mannagrass seed has no strong dormancy and germinates at
a moderate rate in fall or spring. Establishment rate is intermediate.
Hulls are loosely attached and may be readily removed during seed
processing. There are approximately 1,300,000 seeds/lb (+/- 30%). A
sowing rate of 1 lb per/ac of pure live seed will result in about 30
live seeds per square foot. The potential high cost of seed may limit
its use to mixtures with other native grasses. Based on seed size and
seedling vigor alone, a seedling rate of 2 to 5 lbs/ac may be adequate
for a single species stand.

##### Management![](media/image4.jpeg){width="1.5118055555555556in" height="2.502083333333333in"} {#management .Header-3}

There is a lack of information about the management of slender spiked
mannagrass for livestock or other purposes. Succulent growth should
favor palatability, but grazing would be inappropriate or restricted
under the wet environments where this species grows. Seed production
requires extensive irrigation, poorly drained soils, seasonal wetlands,
or shallow water impoundments. Regeneration is favored by disturbance
and the presence of open mud or prolonged moist soil that is sparsely
vegetated. This species may be suited to moist soil management (slow
de-watering, disking, etc.) of impounded wetlands for improving
waterfowl, shorebird, and other wildlife habitat.

##### Limitations and Environmental Concerns {#limitations-and-environmental-concerns .Header-3}

It is difficult to obtain seed of any volume from the wild. In western
Oregon, other mannagrasses, especially western mannagrass, are
considered weeds in low lying fields of Italian ryegrass (*Lolium* spp.)
grown for seed. Apparently, slender-spiked mannagrass is of infrequent
or lesser concern. It is not reported to be a competitive, weedy or
invasive plant species.

##### Cultivars, Improved, and Selected Materials (and area of origin) {#cultivars-improved-and-selected-materials-and-area-of-origin .Header-3}

This species is rarely sold as seed or plants. Availability depends on
wild collections or contract growing with producers who specialize in
native herbaceous plant seed.

##### Prepared By:  {#prepared-by .Header-3}

*Dale Darris*, USDA NRCS Plant Materials Center, Corvallis, Oregon.

##### Species Coordinator:  {#species-coordinator .Header-3}

*Dale Darris*, USDA NRCS Plant Materials Center, Corvallis, Oregon.

##### Edited: 21mar2006 jsp, 17sept2008 dcd; 080919 jsp {#edited-21mar2006-jsp-17sept2008-dcd-080919-jsp .Header-4}

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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*To file a complaint of discrimination write USDA, Director, Office of
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