Chaenactis artemisiifolia

Chaenactis artemisiifolia (A.Gray) A. Gray

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