National Collection of Imperiled Plants

CPC National Collection Plant Profile

Photographer:

V. Crosby

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CPC National Collection Plant Profile

Pleuropogon oregonus

Family:	Poaceae
Common Name:	Oregon semaphore grass
Author:	Chase
Growth Habit:	Graminoid
CPC Number:	3529

Distribution
Protection
Conservation
References

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Photographer: V. Crosby
Image Owner: courtesy USFWS

Pleuropogon oregonus is Not Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

Rae Selling Berry Seed Bank & Plant Conservation Program

Pleuropogon oregonus

The very existence of Oregon semaphore grass has been a recurring question over the past 100 years. In 1886, William C. Cusick first collected this grass in what was once called Hog Valley in northeastern Oregon, and another collection was made in Union, Oregon in 1901. It was not collected again until 1936, when M.E. Peck discovered it in the southern part of the state (in Lake County, Oregon). It was not seen or collected again for nearly 40 years and was reported as presumably extinct or endangered in the late 1970s. In 1979, Jimmy Kagan of the Oregon Natural Heritage Program diligently scoured a site along Mud Creek in Lake County until he found this particular grass (But 1985). This was probably the same location Peck had made his collection 45 years before.

In 1986, USFS botanist Andy Kratz was determined to lead a thorough search for the Hog Valley population. There was no place officially called "Hog Valley", as it was a name that had been used by locals, but was apparently not commonly used any longer. There was no documentation telling him where to look, so he relied on personal communication with people who lived in the region. Mr. Kratz was eventually directed to an enthusiastic landowner in Union County willing to help him in his search. He was successful in finding the previously documented site in "Hog Valley" as well as 3 new locations nearby in Union County, Oregon. He surveyed surrounding counties including Baker, Harney, Grant, Umatilla, Wheeler, and Morrow but made no discoveries (Kratz 1986). Today, scientists are still only aware of the two main populations of this rare plant.

Although the range is so limited, the U.S. Fish and Wildlife Service removed this plant from candidate status in 1996 because the threats from grazing and stream channelization appeared minimal. It is, however, listed as Threatened by the state of Oregon.

Distribution & Occurrence

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State Range

Oregon

Habitat

Pleuropogon oregonus grows in moist meadows and marshland often comprised of gravelly silt loam or clay soil inundated by sluggish water at elevations of around 2450-3950 ft (750 to 1200 m). It is found growing with other grasses and sedges.

Distribution

OR: Eastern Cascades (Lake County), Blue Mountains (Union County)

Number Left

2 populations. 1 in northeastern Oregon (Union County) and one in southern Oregon (Lake County) (ONHDB and Gisler, pers. comm.). All populations are on private pastureland. A portion of a property in Lake County is managed by The Nature Conservancy.

Protection

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Global Rank:	G1	9/12/2008	Guide to Global Ranks
Federal Status:	SC		Guide to Federal Status
Recovery Plan:	No

State/Area Protection

	State/Area	Rank	Status	Date
	Oregon	S1	LT	10/27/1989

Conservation, Ecology & Research

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Ecological Relationships

Pleuropogon oregonus blooms from early June to late July and fruits from late July to mid August. For the number of possible fruits that it could produce, an extremely low number actually develop and are viable. The low fecundity (reproductive success) may contribute to the rarity of Pleuropogon oregonus (But et al. 1985). In the absence of extensive sexual reproduction, this grass spreads extensively by rhizomes. However, this creates large areas of plants that are genetically identical (ONHDB 2000).

Associated Species include: Carex athrostachya, Eleocharis palustris, Beckmannia syzigachne, Deschampsia danthonioides, Glyceria borealis, Hordeum brachyantherum and Poa nevadensis (But et al. 1985).

Threats

� Land drainage for conversion to grazing or cropland (Kratz 1986).
� Low seed set and moderate seed viability significantly reduces sexual reproduction (But et al. 1985).
� Excessive cattle grazing during periods of active plant growth, flowering and seed set.

Current Research Summary

� Tests of the pollen using four enzyme systems suggest approximately 87% viability (But, 1985).
� Germination trials at The Berry Botanic Garden revealed that germination was greatest (100%) under a cold stratification period followed by a constant 68�F (20�C) treatment. When first subjected to 8 weeks of cold stratification and then subjected to alternating 50�F/68�F (10�C/20�C) temperatures, 71% of seeds germinated. Seeds that were placed directly in a 68�F (20�C) chamber without cold stratification had germination of 83%, and of those placed directly in alternating 50�F/68�F (10�C/20�C) temperatures, only 50% germinated (BBG File).
� Investigation of seed production, seed germination and cultivation of this species (Gisler, pers. comm.).
� Taxonomic comparison of the two extant populations (Gisler, pers. comm.).
� Analysis of ecological data to help predict suitable introduction habitats (Gisler, pers. comm.).

Current Management Summary

� Plants are being cultivated for a planned re-introduction project in 2002 (Gisler, pers. comm.).

� Part of one population is on private land that is managed by The Nature Conservancy. They have fenced off the area and left it undisturbed for many years. However, observations indicate that the nearby grazed areas are more dense and lush that the ungrazed, suggesting that limited grazing by cattle may benefit the plant by removing thatch buildup (Welty 2001).

Research Management Needs

� Conduct studies to determine the effect of light cattle grazing after seed has fallen or before plants begin re-growth in the spring.

Ex Situ Needs

� Collect and store seeds from known populations.

References

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Books (Single Authors)

Meinke, R.J. 1982. Threatened and Endangered Vascular Plants of Oregon: An Illustrated Guide. Portland, Oregon: U.S. Fish & Wildlife Service, Region 1. 326p.

ONHP. 2001. Rare, Threatened and Endangered Plants and Animals of Oregon.

Books (Edited Volumes)

James C. Hickman, Editor. 1993 The Jepson manual: Higher plants of California. Berkeley: University of California Press. 1400p.

Electronic Sources

ONHDB. (2000). Oregon Natural Heritage Program Database. Portland, Oregon.

Journal Articles

1938. (Original Publication). Jour. Wash. Acad. Sci. 28: 52-53.

But, P.P.H. 1994. New combinations in Pleuropogon (Poaceae). Novon. 4, 1: 16--17.

But, P.P.H.; Kagan, J.S.; Crosby, V.L.; Shelly, J.S. 1985. Rediscovery and Reproductive Biology of Pleuropogon oregonus. Madro�o. 32, 3: 189-190.

USFWS. 1996. Notice of Reclassification of 96 Candidate Taxa. Federal Register. 61, 40: 7457-7463.

Welty, J. 2001. Summer Intern Report: Native Plant Conservation Program. Bulletin of the Native Plant Society of Oregon. 34, 1: 1, 6-7.

Personal Communications

Gisler, S. 2001. Personal Communication. Steve Gisler, Oregon Department of Agriculture, Plant Conservation Department, Corvallis, Oregon.

Reports

Kratz, A. 1986. 1986 Northeastern Oregon Field Search for Pleuropogon oregonus Chase. Unpublished report. In BBG File.

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This profile was updated on 7/8/2010