CPC National Collection Plant Profile
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Thelypodium eucosmum
Family: |
Brassicaceae |
Common Name: |
Arrow-leaf thelypody |
Author: |
B.L. Robins. |
Growth Habit: |
Forb/herb |
CPC
Number: |
4274 |
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Primary
custodian for this plant in the CPC National Collection of Endangered
Plants is: |
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Edward Guerrant, Ph.D. contributed to this Plant Profile. |
Thelypodium eucosmum
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When in full bloom, the beautiful pink-purple flowered inflorescences and arrow-shaped leaves of Thelypodium eucosmum create spectacular show. These tall and spindly members of the mustard family stand out against the otherwise brown and gray sagebrush-covered hillsides of eastern Oregon. This plant is known only from two counties in eastern Oregon, and is found only within the lower canyons of the Blue Mountains and along the tributaries of the John Day River. There are many populations, but population levels are highly influenced by fluctuating stream levels and yearly rainfall amounts.
Distribution
& Occurrence |
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State Range
Habitat
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• Lower to intermediate elevations in the juniper-sagebrush series of plant communities (Meinke 1982).
• Steep basalt drainages which are wet for part of the year, streambanks in full sun or shade, vernally moist alkaline areas, hillside seeps, and under isolated western juniper trees away from obvious moisture (BLM 2002).
• Associated species include western juniper (Juniperus occidentalis), Great Basin wildrye (Elymus cinereus), big sagebrush (Artemisia tridentata), and rattlesnake brome (Bromus brizaeformis) (BLM 2002). |
Distribution
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OR
OR: Lower canyons of the Blue Mountains in Grant Co. and Wheeler Co.
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Number Left
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As of 2001: 55 populations on BLM land, 2 on National Forest land, and approx. 5 on private land. Populations range from 5 individuals to 5000, but vary greatly from year to year (ONHDB 2000). |
State/Area
Protection
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State/Area |
Rank |
Status |
Date |
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Oregon |
S2 |
LT |
7/12/1995 |
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Conservation,
Ecology & Research |
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Ecological
Relationships
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Thelypodium eucosmum is often characterized as being a biennial or short-lived perennial, and may well often die after flowering once. Hitchcock et al. (1973) refer to it as a perennial that spreads by rootstocks, and note that individual clumps are usually mistaken to be taprooted biennial plants. At the Berry Botanic Garden, the plant behaves as a perennial that can flower for two or more years.
The number of first year plants varies greatly each year depending on the amount of rainfall and other climactic conditions. However, the number of older plants appears to remain more stable despite weather conditions (Halvorson, pers. comm. 2001).
Occasional episodes of significant natural disturbances often benefit the Arrow-leaf thelypody. Many seedlings have been observed in the bare soil created by a wind-thrown western juniper. While limited disturbances may encourage seedling growth, continued disturbances would most likely be detrimental to the population overall (Halvorson, pers. comm. 2001). |
Threats
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Threats, as stated by Halvorson (Halvorson, pers. comm. 2001), include the following:
• Most historical sites were probably extirpated by livestock grazing. Consequently, most of the known populations are in areas not normally grazed by livestock, or grazed lightly. Livestock grazing is also at much lower levels than it was 20 years ago, so little additional damage is being done to Thelypodium eucosmum habitat.
• Recent population declines have been caused by natural events (heavy soil loss or landslides resulting from intense rainfall).
• Alteration of subsurface hydrology caused by an increase in woody species, especially western juniper (Juniperus occidentalis) is a potential threat. Western juniper encroachment has been linked to a documented decrease in stream flow. |
Current Research Summary
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• Germination trials conducted at Lewis and Clark College. Seeds were subjected to either a warm stratification 68°F (20°C) or a cold Stratification 41°F (5°C) for 6 weeks followed by either 59°/41°F (15°C/5°C) alternating temperatures or 68°/50°F (20°C/10°C) alternating temperatures. Seeds subjected to the warm stratification had very low germination (about 5%). Seeds subjected to 6 weeks of cold stratification germinated readily after being removed to the warmer germination chambers. Under alternating 59°/41°F (15°C/5°C) conditions, ~60% of the seeds germinated. Under alternating 68°/50°F (20°C/10°C) conditions, approximately 85% of the seeds germinated (Florance, pers. comm. 2001)
• Germination trials conducted at The Berry Botanic Garden. Plants were subjected to constant 20°C temperatures or alternating 20°/10°C temperatures both with and without an 8 week cold stratification period. Seeds not subjected to the cold stratification did not germinate. Of the seeds subjected to the 8 weeks of cold stratification, those in the constant 20°C chamber had 50% germination while those in the alternating 20/10°C had 71% germinate (BBG file). |
Current Management Summary
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• 50 of the 55 populations on BLM land are in active grazing allotments (Halvorson, pers. comm. 2001).
• One population was subjected to burning. Plants were robust the year after the fire, and two years of monitoring indicated that the population had fully recovered (Halvorson, pers. comm. 2001). |
Research Management Needs
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• Study effect of disturbances on Thelypodium eucosmum (Halvorson, pers. comm. 2001).
• Study soil moisture relationships (Halvorson, pers. comm. 2001). |
Ex Situ Needs
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• Collect and store seeds from across the range.
• Determine optimal germination conditions.
• Determine propagation and reintroduction protocols. |
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Books (Single Authors)
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Eastman, D.C. 1990. Rare and Endangered Plants of Oregon. Beautiful America Publishing Company. 194p.
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Hitchcock, C.L.; Cronquist, A. 1973. Flora of the Pacific Northwest: An illustrated manual. Seattle: Univ. Washington Press.
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Meinke, R.J. 1982. Threatened and Endangered Vascular Plants of Oregon: An Illustrated Guide. Portland, Oregon: U.S. Fish & Wildlife Service, Region 1. 326p.
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Munz, P.A.; Keck, D.D. 1959. A California flora. Berkeley, CA: Univ. California Press. 1681p.
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ONHP. 2001. Rare, Threatened and Endangered Plants and Animals of Oregon.
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Electronic Sources
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BLM. (2002). Arrow-leaf Thelypody. Prineville District BLM. http://www.or.blm.gov/Prineville/Botany/Plant%20Narratives/Arrow-leaf_thelypody.htm. Accessed: 2002.
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ONHDB. (2000). Oregon Natural Heritage Program Database. Portland, Oregon.
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Journal Articles
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1895. (Original Publication). Synop. Fl. No. Amer. 1: 175.
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Florance, E.R. 2001. Personal communication. Edwin Florance, Botany Professor, Lewis and Clark College, Portland, Oregon.
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Schwartz, A. Banking on Seeds to Avert Extinction.
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Personal Communications
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Halvorson, R. 2001. E-mail communication with Rebecca Weaver 11/15/01. Ron Halvorson, Botanist, Prineville District BLM, Prineville, Oregon.
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This
profile was updated on 7/8/2010 |
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