Cirsium scariosum Nutt.
Elk thistle (Cirsium foliosum (Hook.) DC and C. drummondii Torrey & A. Gray misapplied)

Family:  Asteraceae

Habit:  2 to 6 dm. high, perennial, arachnoid-villous stem, corollas pale or white.

Distribution:  Montane coniferous, in meadows and moist places from British Columbia to Baja California and the Rocky Mountains.

Seed unit:  Achene.

Seed:  3 to 5 mm. long, oblong-obovate, more or less compressed, pappus 15 to 30 mm.

Embryo:  Foliar with well developed cotyledons, no endosperm.

Purity instructions:  Pure seed definition:
AOSA: PSU# 50 - Intact achene, with or without one or more of the following structures: beak, bristle, hairs, pappus, wing, or firmly attached floral remnants, provided a true seed with some degree of embryo development can be detected (either by slight pressure or by examination over light).
Piece of broken achene larger than one-half of the original size, unless no seed is present. Seed, with or without pericarp/seed coat; if broken, larger than one-half the original size.
ISTA: PSD#1 – Achene with or without pappus, unless it is obvious that no seed is present.

Average pure seed units per gram:  1,764 seeds per gram (based on AOSA pure seed units only from 1 sample received for testing from 2002).

Range of percent pure seed:  4%

Range of percent inert:  96%

Description of inert:  Plant material, broken seed.