Lomatium cookii
J.S. Kagan
Agate Desert Lomatium
G1Critically ImperiledGlobal Rank
Very highThreat Impact
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.133801
Element CodePDAPI1B250
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderApiales
FamilyApiaceae
GenusLomatium
Other Common Names
agate desertparsley (EN) Agate Desert-parsley (EN) Cook's Lomatium (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-06-05
Change Date1988-08-02
Edition Date2024-06-24
Edition AuthorsBorgias, D., Kagan, J.S., Vrilakas, S. (2013), rev. Johnson (2024)
Threat ImpactVery high
Range Extent250-1000 square km (about 100-400 square miles)
Number of Occurrences6 - 20
Rank Reasons
Lomatium cookii is a perennial herb of the western United States that is a narrow endemic, restricted to two small valley bottoms in Jackson and Josephine counties in southwestern Oregon. Fairly complete surveys of this species' limited vernal pond habitat have been conducted, and 32 occurrences were found with a total of about 50,000 reproductively mature plants. Both of the areas in which the species occurs are being threatened by residential and urban development and one area is also threatened by mining and off-road vehicle traffic.
Range Extent Comments
Lomatium cookii is a narrow, local endemic restricted to two counties in the southwestern portion of Oregon, USA. It is limited to two small areas: the Agate Desert area north of the city of Medford, Jackson County, and the Illinois River Valley area near Cave Junction, Josephine County. Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1993 and 2024 (iNaturalist 2024, NatureServe 2024, OBIC 2024, OSU 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1993 and 2024, it is estimated that there are twenty extant occurrences range-wide (iNaturalist 2024, NatureServe 2024, OBIC 2024, OSU 2024, SEINet 2024).
Threat Impact Comments
Currently, habitat destruction from land development (industrial, commercial, and residential), mining, and ORV use are the major threats to this species. Of the fifteen occurrences in the Agate Desert area, eleven have the potential for commercial and industrial development. The remaining four are located in Nature Conservancy preserves, a state wildlife management area, and a county park. Mining activity and residential development threaten the Illinois River Valley area. Three of the twenty occurrences are near mining activity while the remaining sites in public ownership (Bureau of Land Management) are also exposed to this risk. Expansion of the airport will likely impact portions of that occurrence (OBIC 2024, USFWS 2019).
Grazing by cattle at more than a moderate level is also a threat to this species. Of the 35 known populations, six are on land used for grazing, although most of the Agate Desert area has been historically grazed. Cattle and horses have been observed eating L. cookii, and populations have not been found at heavily grazed sites. Gophers (mostly in mound and flank areas) and possibly wireworms are predators; however, under natural conditions, they are not considered threats to the species.
Off-road vehicular traffic is a concern for many of the occurrences with mention of ORV tracks running through the population and severely damaging the habitat, especially in the important, large populations in the alluvial floodplain areas in the Illinois Valley.
Thatch buildup from Taeniatherum caput-medusae (Medusahead) may contribute to the observed decrease in L. cookii population density after several years without grazing. Thatch reduction by mechanical removal or burning has been demonstrated to increase seedling survival for L. cookii. The second year post-burn ratio of seedlings relative to the number of reproducing plants prior to the burn was between 4 and 100 times as great as the number of seedlings per adult in unburned areas on the Agate Desert Preserve. Other invasive species such as Yellow Starthistle (Centauria solstitialis) may compete with seedlings and juvenile plants of L. cookii for light and water. Lack of fire at other occurrences has lead to increased tree and shrub density. Occurrences that are mowed or burned have seen steady or increasing populations (USFWS 2019, OBIC 2024).
Grazing by cattle at more than a moderate level is also a threat to this species. Of the 35 known populations, six are on land used for grazing, although most of the Agate Desert area has been historically grazed. Cattle and horses have been observed eating L. cookii, and populations have not been found at heavily grazed sites. Gophers (mostly in mound and flank areas) and possibly wireworms are predators; however, under natural conditions, they are not considered threats to the species.
Off-road vehicular traffic is a concern for many of the occurrences with mention of ORV tracks running through the population and severely damaging the habitat, especially in the important, large populations in the alluvial floodplain areas in the Illinois Valley.
Thatch buildup from Taeniatherum caput-medusae (Medusahead) may contribute to the observed decrease in L. cookii population density after several years without grazing. Thatch reduction by mechanical removal or burning has been demonstrated to increase seedling survival for L. cookii. The second year post-burn ratio of seedlings relative to the number of reproducing plants prior to the burn was between 4 and 100 times as great as the number of seedlings per adult in unburned areas on the Agate Desert Preserve. Other invasive species such as Yellow Starthistle (Centauria solstitialis) may compete with seedlings and juvenile plants of L. cookii for light and water. Lack of fire at other occurrences has lead to increased tree and shrub density. Occurrences that are mowed or burned have seen steady or increasing populations (USFWS 2019, OBIC 2024).
Ecology & Habitat
Description
Lomatium cookii is a perennial herb, about 6" to 20" tall, with yellow flowers, a leafless stem, smooth leaves and large, corky thickened fruit.
Diagnostic Characteristics
Lomatium cookii can be distinguished from the common L. utriculatum, with which it grows, by L. cookii's linear, narrow involucel bracts compared to the broad L. utriculatum bracts, its acaulescent habit (L. utriculatum is obviously caulescent), its longer ultimate leaf segments, and larger, corkier fruits. Also, L. utriculatum does not grow in pools (it grows on the mounds). L. macrocarpum is distinguishable from L. cookii by L. macrocarpum's pubescent herbage, pale to tan flowers, long involucel bracts that extend beyond the flowers, and narrow, winged fruits. L. cookii seedlings can be distinguished from other Lomatium seedlings by their lack of a reddish, scabrous petiole and their fewer and more linear ultimate leaf segments.
Habitat
In the Agate Desert area, Lomatium cookii grows along the margins and less frequently on the bottoms of vernal pools or the tops of the mounds, usually with native forbs and introduced annual grasses in a mound-vernal pool habitat. Native plant species include Alopecurus geniculatus, Deschampsia danthonioides, Danthonia californica, Brodiaea sp., Lupinus sp., Limnanthes floccosa ssp. grandiflora, and Limnanthes floccosa ssp. floccosa. The pools that support Lomatium cookii generally have either stony bottoms or shallow layers of clay and contain standing water from approximately December through March, April or May. The mounds are relatively rock-free, with loan and clay loam soils.
In the Illinois Valley, it occurs on seasonally moist alluvial floodplains, with native bunchgrasses, Poa scabrella (Pine Bluegrass) and Danthonia californica (California Oatgrass), adjacent to Pinus ponderosa-Quercus garryana (Ponderosa Pine-Oregon White Oak) Savanna with Ceanothus cuneatus (Common Buckbrush) and Arctostaphylos species (manzanita). The habitats are almost all surrounded by serpentine, Pinus jeffreyi (Jeffrey Pine) Upland Savannas (USFWS 2019, NatureServe 2024, OBIC 2024, OSU 2024).
In the Illinois Valley, it occurs on seasonally moist alluvial floodplains, with native bunchgrasses, Poa scabrella (Pine Bluegrass) and Danthonia californica (California Oatgrass), adjacent to Pinus ponderosa-Quercus garryana (Ponderosa Pine-Oregon White Oak) Savanna with Ceanothus cuneatus (Common Buckbrush) and Arctostaphylos species (manzanita). The habitats are almost all surrounded by serpentine, Pinus jeffreyi (Jeffrey Pine) Upland Savannas (USFWS 2019, NatureServe 2024, OBIC 2024, OSU 2024).
Ecology
Lomatium cookii grows in vernally wet habitats and it blooms and fruits early in the spring. It has been observed to survive wildfire and experimental and management burns quite well. There appears to be a source-sink relationship between the habitat provided in some vernal pools relative to the surrounding mounds. At the Jackson County International Airport, leveling of the soil mounds in some areas created a soil layer over the hardpan bottom that mimics the vernal pool margins, leading to an extensive population of the plant in a non-natural setting. That particular population is ungrazed, but mowed annually around the time that annual grasses cure.
Reproduction
All reproduction occurs via seed production. Lomatium cookii blooms from mid-March through mid-May depending on the season. Some initiate flowering the last week of February. Plants in pools generally flower 1 week earlier than those on pool flanks or mounds, and some rooted in pools flower under water. There are usually 2-5 flowering umbels, 8-20 umbellets, and 100-250 flowers. The earliest inflorescences are almost all male, with undeveloped ovaries; later flowers are perfect and produce almost all of the fruits. Flowers are protogynous, with the stigmas exposed and receptive before anther dehiscence in the same flower, but some had receptive stigmas after anther dehiscence as well, which may allow for self-pollination. The main insect pollinator is a small bee of the Adrenae family; wind and other invertebrates are also likely pollinators (Brock 1987). Fruits begin development 14-20 days after stigma exsertion, and mature in 4-5 weeks. The dispersal distance is 30-60 cm. Fruits are knocked off the plant by wind or other physical disturbance. Flotation on the ponds does not seem to be a dispersal mechanism (Brock 1987).
Seeds require 7 weeks to 4 months stratification at cool temperatures to germinate. Seed germination in the field begins the first week of February, peaking during the first week, but continuing for more than a month. Seeds in pools germinate about a week later than those on pool flanks or mounds.
Both non-flowering and mature plants grow fastest from February to late April when they start to dry up. Mature plants also grow at a more moderate rate from mid-late fall to December.
Seeds require 7 weeks to 4 months stratification at cool temperatures to germinate. Seed germination in the field begins the first week of February, peaking during the first week, but continuing for more than a month. Seeds in pools germinate about a week later than those on pool flanks or mounds.
Both non-flowering and mature plants grow fastest from February to late April when they start to dry up. Mature plants also grow at a more moderate rate from mid-late fall to December.
Terrestrial Habitats
Forest EdgeSavannaGrassland/herbaceous
Palustrine Habitats
TEMPORARY POOL
Other Nations (1)
United StatesN1
| Province | Rank | Native |
|---|---|---|
| Oregon | S1 | Yes |
Threat Assessments
| Threat | Scope | Severity | Timing |
|---|---|---|---|
| 1 - Residential & commercial development | Large (31-70%) | Serious or 31-70% pop. decline | Moderate - low |
| 1.1 - Housing & urban areas | Restricted (11-30%) | Serious or 31-70% pop. decline | Moderate - low |
| 1.2 - Commercial & industrial areas | Restricted (11-30%) | Serious or 31-70% pop. decline | Moderate - low |
| 2 - Agriculture & aquaculture | Restricted (11-30%) | Serious or 31-70% pop. decline | High (continuing) |
| 2.1 - Annual & perennial non-timber crops | Restricted (11-30%) | Serious or 31-70% pop. decline | Moderate (short-term) |
| 2.3 - Livestock farming & ranching | Restricted (11-30%) | Moderate or 11-30% pop. decline | High (continuing) |
| 3 - Energy production & mining | Restricted (11-30%) | Serious or 31-70% pop. decline | High - moderate |
| 3.2 - Mining & quarrying | Restricted (11-30%) | Serious or 31-70% pop. decline | High - moderate |
| 6 - Human intrusions & disturbance | Large (31-70%) | Moderate or 11-30% pop. decline | High (continuing) |
| 6.1 - Recreational activities | Large (31-70%) | Moderate or 11-30% pop. decline | High (continuing) |
| 7 - Natural system modifications | Large (31-70%) | Moderate or 11-30% pop. decline | High (continuing) |
| 7.1 - Fire & fire suppression | Large (31-70%) | Moderate or 11-30% pop. decline | High (continuing) |
| 8 - Invasive & other problematic species, genes & diseases | Large - restricted | Moderate - slight | High (continuing) |
| 8.1 - Invasive non-native/alien species/diseases | Large - restricted | Moderate or 11-30% pop. decline | High (continuing) |
| 8.2 - Problematic native species/diseases | Restricted (11-30%) | Slight or 1-10% pop. decline | High (continuing) |
Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (2)
Oregon (2)
| Area | Forest | Acres |
|---|---|---|
| South Kalmiopsis | Siskiyou National Forests | 104,477 |
| South Kalmiopsis | Siskiyou National Forests | 104,477 |
References (11)
- Brock, R. 1987. The ecology of LOMATIUM COOKII, an endangered species of the Rogue Valley, Oregon. Unpublished document for Oregon Field Office of The Nature Conservancy. 31 pp.
- Flora of North America Editorial Committee (FNA). 2024. Flora of North America north of Mexico. Vol. 13. Magnoliophyta: Geraniaceae to Apiaceae. Oxford Univ. Press, New York. xxiv + 566 pp.
- iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
- Kagan, J.S. 1986. A new species of Lomatium (Apiaceae) from southwestern Oregon. Madrono 33(1): 71-75.
- Kagan, J.S. 1987. Draft status report for LOMATIUM COOKII. Unpublished document prepared for U.S. Fish and Wildlife Service. Portland, Oregon. 51 pp.
- Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
- Kaye, T. N. 2003. Lomatium cookii: Population monitoring in the Illinois Vallye, Josephine County, Oregon. January 2003 progress report. Bureau of Land Management, Medford District and Institute of Applied Ecology, Corvallis, Oregon.
- NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
- Oregon State University (OSU). 2024. Oregon Flora website. Oregon State University Herbarium at Oregon State University. Online. Available: https://oregonflora.org/ (accessed 2024).
- Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).
- U.S. Fish and Wildlife Service. 2019. 5-year Review for<i> Lomatium cookii</i> (Cook’s desert parsley, Cook’s lomatium), U.S. Fish and Wildlife Service, Roseburg, Oregon. September 27, 2011. 9 pp. https://ecosphere-documents-production-public.s3.amazonaws.com/sams/public_docs/species_nonpublish/2910.pdf