Silybum marianum (L.) Gaertner
Family: Asteraceae, Tribe: Cynareae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
Carduus marianus L., Cirsium maculatum Scop.
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
milkthistle, variegated thistle
Primary Disseminule Type
Description (diagnostics are in brown)
Fruit a cypsela, broadly oblong to obovate, somewhat compressed, slightly gibbous, cross-section elliptic, 6–8 mm long x 2.8–3.2 mm wide x 1.8–2.2 mm thick. Surface mottled (sometimes creating some striping) black and brown over a yellowish-tan base, smooth to mildly rippled, shiny. Pappus somewhat persistent to eventually deciduous, bristles mostly 15–20 mm long, numerous, cream-colored, flat, outer scabrid, inner fine, all fused at the base to form a ring that detaches as a unit.
Style base broad (ca. 0.9 mm long x 0.9 mm wide), blunt, cylindrical to lobed, surrounded by a yellowish, raised collar 1.4–1.6 mm across.
Fruit attachment scar basal, somewhat obliquely angled.
Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)
AUQP, NZBORIC, NZBPI