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Status: OBHDB List 1 (threatened with extinction throughout its range) Federal: Candidate State: Listed Endangered BLM: Bureau sensitive Geographic Distribution: Erigeron decumbens var. decumbens is endemic to the Willamette Valley. Historical records document that the species was once found in every county in the Willamette Valley except for Multnomah. There are 45 EOR's in the ONHP data base, but 18 are historical sites are apparently no longer extant. One large population in west Eugene was destroyed in 1996. Extant populations are still known from most counties, but in many counties there are only one or two populations. There are 13 EOR's in west Eugene. Erigeron decumbens var. robustior, the other variety of the species, is found only in Humboldt and Trinity Cos. of California (Strother & Ferlatte, 1988). Habitat Description: This species is restricted to native prairies but is found in a variety of prairie communities. Outside of west Eugene, most populations are in upland prairie communities, whereas many of the west Eugene populations are in wet prairie. Most populations are in sites that are relatively undisturbed, high quality prairie remnants, with a diversity of native forb and grass species present. A few populations are known from more degraded sites, but these populations are generally small in size. Soils of the wet prairie sites are mapped as Dayton and Natroy series. The soils of upland sites are very diverse. Growth Habit: Herbaceous taprooted perennial, decumbent and often purplish at the base, 1.5 -7 dm. tall, appressed -hairy. Usually individual plants are fairly small but occasional large plants with 50 to 100 or more shoots can occur. Leaves: Basal leaves and most of the cauline ones triple nerved, up to 25 cm. long (including the long petiole) and 1 cm. wide. Flowers: Heads 1 -20, central yellow disk 8 -15 mm. wide, of tiny, tubular flowers, involucre 3.5 -6 mm. high; ray flowers 20 -50, light to deep pink, 6 -12 mm. long; 1 -2 mm. wide; disk corollas 2.5 -4.5 mm. long. Fruit: Achene with pappus. Pappus with about 12 -16 fragile bristles, occasionally with some obscure outer setae. Seed Germination Rate, Seed Bank Persistence: Seed germination and seed viability are not known. Seed production at some sites in 1993 was estimated to be between 156 -168 - seeds per head (Clark et al. 1994). So far efforts to germinate seeds have not been very successful. Phenology: Vegetative shoots emerge in spring. Flowering occurs from June to early to mid -July and sporadically through late August (Meinke 1980); peak bloom occurs 20 June through 1 July (Kagan and Yamamoto 1987) in years with sufficient late spring rainfall. In 6