Willamette Daisy

Erigeron decumbens var. decumbens

Description

The Willamette daisy is a perennial, herbaceous plant. It grows 0.6-2.4 in (15-60 mm) tall, with erect or sometimes prostrate stems. The basal leaves often wither prior to flowering and are mostly linear, 2-5 in (5-12 cm) long and 0.1-0.2 in (3-4 mm) wide. The flowering stems produce two to five daisy-like heads, with pinkish to pale-blue ray florets and yellow disk florets.

Habitat

The Willamette daisy occurs in seasonally flooded wet prairies with hydric soil.

Distribution

The Willamette daisy is a locally evolved (or endemic) variety that is limited in distribution to the Willamette Valley of Oregon. The valley is about 130 mi (209 km) long and 20-40 mi (32-64 km) wide. It is an alluvial floodplain with an overall northward gradient.

Threats

The Willamette daisy once occurred throughout much of the Willamette Valley. Most of its original habitat was destroyed through conversion into agricultural, residential, and commercial land-uses. No observations were made of this rare plant between 1934 and 1979, but it was "rediscovered" in 1980 in Lane County, Oregon, and has since been identified at 28 sites in Benton, Lane, Linn, Marion, and Polk Counties. It occurs in a total of about 286 acres (116 hectares) of habitat. Ecological conversions of its habitat are ongoing threats to the Willamette daisy, as are herbicide spraying to control vegetation in its roadside habitat, grazing by livestock, and other disturbances.

Conservation and Recovery

Two of the three largest populations of the Willamette daisy on property owned by the U. S. Army Corps of Engineers and on land of the Nature Conservancy are being managed to benefit native prairie species and are relatively secure. The third large site occurs on private land and is not managed to conserve native prairie species or protected from habitat loss. At least 24 of the 28 known sites of the Willamette daisy occur on private land, and are threatened by changes in land use and disturbances. The best habitats of this rare plant on private land should be acquired and set aside as ecological reserves, or conservation easements should be negotiated.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

U. S. Fish and Wildlife Service, Oregon State
Office
2600 S. E. 98th Ave, Suite 100
Portland, Oregon 97266-1398
Telephone: (503) 231-6179
Fax: (503) 231-6195

Reference

U. S. Fish and Wildlife Service. 25 January 2000. "Endangered and Threatened Wildlife and Plants: Endangered Status for Erigeron decumbens var. decumbens (Willamette Daisy) and Fender's Blue Butterfly (Icaricia icarioides fenderi) and Threatened Status for Lupinus sulphureus ssp. kincaidii (Kincaid's Lupine)." Federal Register 65 (16):3875-3890.