Red-root Yampah - Center For Plant Conservation
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Plant Profile

Red-root Yampah (Perideridia erythrorhiza)

These feathery plants are capped by small white flowers arranged in "umbels." Photo Credit: Oregon Department of Agriculture
  • Global Rank: G2 - Imperiled
  • Legal Status: N/A
  • Family: Apiaceae
  • State: OR
  • Nature Serve ID: 151563
  • Date Inducted in National Collection: 03/08/1989

How can simply changing a species' name help to protect it Perideridia erythrorhiza is found on both sides of the Cascade Range in southwestern Oregon. Significant morphological and biological differences between plants at the two locations have led researchers to believe that they should be considered different subspecies or varieties, or even different species altogether. This splitting into two different taxa may help protect the plants in the long run. There are very few populations in the eastern Cascades, and if split from the western plants the number of populations of this "new" species would be low enough to warrant listing. This would help ensure the survival of the relatively small number of plants in the east. This plant and others in the genus Perideridia were an important food source for Native Americans in the region. It is a member of the carrot family, and it's tuberous roots are both sweet tasting and nutritious (Meinke, 1998). But please, don't go out and eat the rare plants.

Where is Red-root Yampah (Perideridia erythrorhiza) located in the wild?


West of the Cascades, Perideridia erythrorhiza is found growing in low swales, moist prairies, valleys and pastureland at lower elevations. It is often found in heavy, poorly drained soils. Populations east of the Cascades are most often found at the margins of coniferous forests and in high elevation meadows.


OR: Klamath Mountains, and east and west sides of Cascade Mountains

States & Provinces:

Red-root Yampah can be found in Oregon

Which CPC Partners conserve Red-root Yampah (Perideridia erythrorhiza)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

Nature Serve Biotics
  • 05/02/2017

Known only from southwestern and southcentral Oregon where there are about 20 extant occurrences. There are less than 50,000 plants in total, 80% of them located on only 4 sites. None of the large populations are protected. Occurrences are in valley bottomlands - areas with high development pressures.

  • 01/01/2010

Housing development (Meinke 1982). Agricultural development (Meinke 1998). Grazing, reduces seed set and reduces survival over the years as resources are depleted and not replaced (Meinke 1998). Low population numbers, contributing to low genetic d

  • 01/01/2010

As of 1998: There were approximately 21 populations located in three major geographical areas (Roseburg, Grants Pass, and Klamath Lake). Sizes ranged from fewer than 100 to more than 250,000 individuals. At least 3 populations had >10,000 individuals (Meinke 1998).

  • 01/01/2010

Molecular comparison of eastern and western populations using cpDNA (chloroplast DNA). The results are not complete and not published. The results tentatively support the speculation that the to populations are genetically distinct. (Casey Baldwin, Graduate Student at University of Idaho in Meinke 1998). Taxonomic investigation of eastern and western populations. Morphological, biological and habitat data support the separation of eastern and western populations into two distinct taxa, either separate species or subspecies. There were no significant or consistent differences between east and west populations in time of flowering and fruiting, and germination requirements. However, significant differences were found in reproductive output, mature fruit size, leaf biomass, tuber mass, tuber length, tuber color, timing of germination, and timing of spring growth. A total of 15-20 traits were compared using Principal Components Analysis (PCA), a statistical method used to evaluate quantitative and qualitative traits of taxonomic value. The researchers suggest that the east and west populations should be treated as separate subspecies or varieties (Meinke 1998). Re-introduction and conservation (Kim Roberts, Graduate research at Oregon State University). Germination trials at the Berry Botanic Garden in which the seed had been stored for approximately 10 years yielded between 0 and 40% germination depending on the treatment. When the seed had only been stored for one or two years, between 80 and 90% of seeds germinated depending on the treatment (BBG File).

  • 01/01/2010

Seeds have been collected from 8 locations in Douglas and Josephine Counties (all west of the Cascades). Seeds represent bulk collections (no separation of maternal lines). Seeds stored at The Berry Botanic Garden Seed Bank for Rare and Endangered Plants of the Pacific Northwest. Plants are being cultivated by seed in the greenhouse to develop large plants for introduction onto public (BLM) land by Oregon Department of Agriculture staff (Gisler, pers. comm.). Two new populations were introduced onto Bureau of Land Management (BLM) land in 2001 by Oregon Department of Agriculture staff. Introduced populations will be monitored in coming years to determine success (Gisler, pers. comm.).

  • 01/01/2010

Habitat burning to reduce competition or pollinators (Meinke 1998). Habitat burning to reduce overcrowding and shading (Meinke 1998). Additional inventory of federal and state owned lands (Meinke 1998). Population reintroduction or augmentation. Plants can be started in the greenhouse and transplanted to the field (Meinke 1998). Purchase or land-trade agreements with private owners of the larger, more pristine populations (Meinke 1998). Determine if gene flow occurs between population centers. Determine if east and west populations are capable of interbreeding with each other. Further genetic studies to clarify relationship between east and west populations.

  • 01/01/2010

Collect and store genetically representative seed samples from populations across the range. Keep maternal lines separate when collecting seed. Determine long term viability of seeds under various storage conditions. Store seeds under appropriate conditions. Recollect seeds as necessary in order to maintain suitable numbers of viable seeds. Determine effective and efficient germination and propagation protocols.


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Taxon Perideridia erythrorhiza
Authority (Piper) Chuang & Constance
Family Apiaceae
CPC Number 3301
ITIS 29803
Common Names red-root yampah | Western yampah
Associated Scientific Names Perideridia erythrorhiza
Distribution OR: Klamath Mountains, and east and west sides of Cascade Mountains
State Rank
State State Rank
Oregon S2
Ecological Relationships

Many tiny white flowers are packed into dense, showy clusters (umbels), which attract a wide array of pollinators, including small native bees and flies. Depending on its size, an individual plant may have up to 20 or more umbels. Dense patches of plants attract large numbers of pollinators. Perideridia erythrorhiza is primarily an out-crossing species, but greenhouse studies have shown that it is self-compatible. Field studies have not been conducted to determine if any self-pollination occurs in nature. Umbels toward the top of the plant open first, followed by those lower on the plant. Both east and west populations exhibit the same pattern (Meinke 1998).Time of flowering may be anywhere between late July and the end of September. The Josephine County populations (west, high elevation) and Klamath County (east, high elevation) plants flower before the Douglas County (west, low elevation) plants do. This seems the opposite of what is expected. One would expect the plants in low, dry areas would bloom before those in more moist, high elevations. Each fruit contains two ovules, which at maturity, separate into two one-seed units. Many fruits may only have one seed. The size and shape of the fruit varies with elevation, like that of flowering time. The Josephine and Klamath County populations have larger seeds, which are longer than they are wide, while the Douglas County plants produce smaller, ovoid (more round) shaped fruit (Meinke 1998). The amount of energy allocated to reproduction varies between the east and west populations. In 1996 and 1997, all plants growing on the west side of the Cascades produced two times the number of seeds as those on the east side due to a greater number of umbels per plant. What is interesting is that there was no significant difference in biomass between the plants on either side of the mountains. Therefore, plants in the west are allocating two times the resources to reproduction than plants in the east. Plants in the east, however, have a slightly greater leaf biomass (allowing them to make the most of the shorter growing season) and a significantly greater tuber biomass to above ground biomass ratio (thereby helping established plants survive and re-grow year after year) than plants in the west. These differences may have a genetic basis. Researchers believe that Eastern plants are genetically adapted to survive in the harsher eastern habitats by relying more on retention of established plants than seedling recruitment to maintain population levels (Meinke 1998). When seeds are dispersed in the fall, they are dormant, and must go through a period of moist chilling before they will germinate. Seeds germinate in early spring, produce one or two entire leaves and whither in the summer, 8 to 12 weeks after germination. A single tuber less than 1cm long develops. Plants do not flower in their first year (Meinke 1998).Tubers must also be chilled for a period of about 8 weeks before they will re-sprout. Both plants grown from seed in the greenhouse and tubers collected from the wild exhibited the same pattern when grown in the greenhouse. Root biomass did not affect the spouting date. Eastern plants sprouted about 10 days earlier than plants from the west. This early sprouting may be an adaptation to the cooler temperatures and shorter growing season of the eastern Cascades. Plants may remain dormant if conditions are not favorable for growth (Meinke 1998).The tuberous roots of Perideridia erythrorhiza have contractile ridges, which allow them to remain buried under the soil as they grow. The size, shape, and color of tubers varies greatly between the east and west populations. Tubers of plants found growing in the west are long, with a narrow elongated section many times longer than the bulbous end. The longest tuber observed on a plant growing in the west was 14.6 inches long. The tubers of plants growing on the east are much shorter--the longest found was only 7.8 inches long. They are thicker--shaped much like a torpedo, and lack the long """"goose neck"""" characteristic of the western plants. The most striking difference between the tubers of the east and west plants is their color. Tubers from the west (Douglas and Josephine Counties) have a brick to cherry red inner-epidermal surface. This is what gives us the common and scientific names-""""erythrorhiza"""" means """"red root."""" The plants in the east, however, have tubers ranging in color from off-while to chestnut brown (Meinke 1998).The populations on the west side of the Cascades are the more threatened although they are the most numerous. They are highly fragmented, and many populations are small (under 100 individuals). Many are on private land, which is not subject to federal and state regulations. There are much fewer populations on the eastern side of the Cascades, and they are scattered widely (Meinke 1998).

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