Acamptopappus sphaerocephalus (A. Gray) A.Gray.
Habit: Low (to 1 m.) much-branched desert shrub with white bark.
Distribution: Found in gravelly or rocky soils, on flats or slopes in deserts to juniper woodlands; in the mountains and deserts of southern Californiato Utah, Nevada, and Arizona.
Seed unit: Achene.
Seed: Achene less than 3 mm. long, densely long-hairy, hairs white to bronze. Pappus of stiff, widely spreading bristles.
Embryo: Foliar embryo, 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# 5 - Achene with or without pappus or bristle, unless it is obvious that no seed is present.
Average pure seed units per gram: 1,015 seeds per gram (based on AOSA pure seed units only from 7 samples received for testing from 1998 to 2004).
Range of percent pure seed: 47 to 59%
Range of percent inert: 38 to 52%
Description of inert: Plant material, dead insects.
Planting instructions: 400 seeds, TB, 14 days @ 20°C; for fresh and dormant seed, prechill recommended.
References: (link to main reference page)
Hickman, J.C., Ed. 1993. p. 188.
Munz, P.A. and D.D. Keck. 1968. p. 1168.
Ransom Seed Laboratory