Isocoma menziesii (Hook & Arn.) G. Nesom
Coastal Goldenbush (syn. Haplopappus venetus (Kunth) S.F. Blake)
Habit: Subshrub, mat forming to 2 meters, yellow flowers.
Distribution: Found in coastal and inland sandy soils in central and south coastal California, the Channel Islands and Baja California. Isocoma menziesii is highly variable and complex with three varities: menziesii, sedoides, and vernonioides.
Seed unit: Achene.
Seed: Silky-hairy, tan-white, 3.5 mm. long with pappus 3 to 5 mm. long.
Embryo: Well-developed cotyledons with 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#1 – Achene with or without pappus, unless it is obvious that no seed is present.
Lab notes: There are often many immature, shriveled fruits.
Average pure seed units per gram: 2,081 seeds per gram (based on AOSA pure seed units only from 46 samples received for testing from 1993 to 2002).
Range of percent pure seed: 8% to 56%
Range of percent inert: 43% to 90%
Description of inert: Broken seed, sticks, plant material, 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. 295.
Ransom Seed Laboratory
Smith, C.F. 1998. p. 170.