Chaenactis artemisiifolia (A.Gray) A. Gray
Pincushion
Family: Asteraceae
Habit: Annual, to 20 dm., whitish, scaly-puberulent below and branched above middle.
Distribution: Found on open slopes and disturbed areas in the Transverse and Peninsular Ranges of Southern California and northern Baja California.
Seed unit: Achene.
Seed: Compressed achene, 4 to 7 mm. long, without pappus.
Embryo: Foliar embryo.
Purity instructions: Pure seed definition:
AOSA: PSU# 27 - Intact achene whether or not a seed is present. 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, unless it is obvious that no seed is present.
Lab notes: Transparent, obviously empty achenes called inert. Use of a diaphanoscope is helpful.
Average pure seed units per gram: 2,239 seeds per gram (based on AOSA pure seed units only from 4 samples received for testing from 1994 to 2004).
Range of percent pure seed: 48 to 67%
Range of percent inert: 32 to 51%
Description of inert: Plant material, broken seed.
Planting instructions: 400 seeds, TB, 21 days; for fresh and dormant seed, prechill recommended.
References: (link to main reference page)
Hickman, J.C., Ed. 1993. p. 224.
Ransom Seed Laboratory
