The Willamette daisy was listed as endangered 2000. Critical habitat was designated in 2006.

Description and Life History

Willamette daisy is a perennial herb in the composite family (Asteraceae) and can reach 15-62 cm (6-24 in) tall. Basal leaves are 5-18 cm (2-7 in) long and less than 1.2 cm (0.5 in) wide, becoming gradually shorter along the stem. The flowering stems, which are taller than the vegetative stems, produce 2 to 5 flower heads. The flowers are daisy-like, with yellow centers and 25-50 pinkish to blue rays, often fading to white with age. Flowering typically occurs during June and early July.

Habitat

This species occurs on alluvial soils (deposited by flowing waters). The Willamette daisy occurs on soils in the Wapto, Bashaw and Mcalpin Series (NRCS mapped soil unit STATSGO 81). The species is known to have been extirpated (destroyed or no longer surviving) from an additional 19 historic locations. Willamette daisy populations are known mainly from bottomland but one population is found in an upland prairie remnant.

Reasons for Decline

Prior to European settlement, prairie habitat was maintained by fire, which prevented the establishment of woody species. Willamette Valley prairie is considered to be among the rarest habitats in western Oregon and is threatened by fragmentation, agriculture and urban growth. Most sites are small and privately owned and few sites are in protective ownership.

Range

The Willamette Daisy is endemic to Oregon's Willamette Valley. Historically, this plant was likely widespread throughout the Valley. Currently, 18 sites are known, distributed over an area of 700,000 hectares (1.7 million acres), between Grand Ronde and Goshen, Oregon.

References and Links

U.S. Fish and Wildlife Service. 2000. 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 65:3875-3890. http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2000_register&docid=fr25ja00-19