Hemizonia fasciculata (DC.) Torrey and A. Gray
Tarweed
Family: Asteraceae
Habit: Annual, stems 1 to 10 dm. high. Fall-flowering xerophyte, glandular and very aromatic.
Distribution: Frequently found in coastal sage scrub, oak woodland, and grassland from California’s central coast to Baja California.
Seed unit: Achene.
Seed: Dimorphic: Ray achenes 2 to 3 mm., beaked, three-angled, with no pappus. Disk achenes 2.5 to 3 mm. with 5 to 12 pappus scales.
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 #4 – Achene, with or without pappus, unless it is obvious that no seed is present.
Lab notes: Samples are often heavily contaminated with other species.
Average pure seed units per gram: 2,295 seeds per gram (based on AOSA pure seed units only from 48 samples received for testing from 1993 to 2004).
Range of percent pure seed: 13 to 33%
Range of percent inert: 64 to 83%
Description of inert: Plant material, broken seed, stone, dirt, sclerotia.
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.282.
Munz, P.A. and D.D. Keck. 1968. p. 1120.
Ransom Seed Laboratory
