Eriogonum umbellatum Torrey.
Sulfur flower

Family:  Polygonaceae

Habit:  Shrub, 10 to 200 cm. with densely tomentose leaves (esp. below); flowers yellow becoming reddish.

Distribution:  Abundant in dry, open, often rocky places; California to western Canada, Colorado and New Mexico.  An extremely variable plant.

Seed unit:  Three-sided achene.

Seed:   2 to 5 mm. long, glabrous, lance ovoid, outer wall (pericarp) firm, brittle.

Embryo:  Peripheral, curved embryo with hard, starchy endosperm.

Purity instructions:   Pure seed definition:
AOSA:  PSU #29 – Intact achene with or without perianth, whether or not a seed is present.  Pieces of broken achene larger than one-half of the original size, unless no seed is present.

Lab notes:  Often achenes with floral parts are immature and empty.

Average pure seed units per gram:  407 seeds per gram (based on AOSA pure seed units only from 23 samples received for testing from 1992 to 2001.

Range of percent pure seed:   50% to 95%

Range of percent inert:  4% to 49%

Description of inert:   Broken seed, plant material, live insects.

Planting instructions:  400 seeds, TB, 21 days @ 20°C; for fresh and dormant seed, prechill recommended.

References: (link to main reference page)
Hickman, J.C., Ed.  1993.  p. 880.
Munz, P.A. and D.D. Keck.  1968.  p. 336.
Ransom Seed Laboratory