Rhaponticum repens (L.) Hildalgo
Family: Asteraceae, Tribe: Cynareae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
Centaurea repens L., Acroptilon repens (L.) DC.
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
creeping knapweed, Russian knapweed
Primary Disseminule Type
Description (diagnostics are in brown)
Fruit a cypsela, obovate or broadly elliptic, sometimes slightly curved in lateral view, compressed, cross-section ± elliptic, 2–4 mm long x 1.3–2.5 mm wide x 0.7–1.4 mm thick, base narrowed and truncate. Surface glabrous, smooth, with a slight sheen and numerous low longitudinal ridges, ivory to pale gray, occasionally green- or yellow-tinged. Pappus a whorl of white, unequal bristles 6–11 mm long, lower portion minutely barbed and upper portion plumose, early deciduous.
Style base variable, cream or light yellow to light brown, ± cylindrical, surrounded by a slightly depressed, whitish ring.
Fruit attachment scar near base but somewhat lateral (but not in hook-like depression), variable in shape and color, often brown, granular.
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, AUWP, NZBORIC, NZBPI