Thlaspi arvense L.

Family: Brassicaceae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)


Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

field pennycress

Primary Disseminule Type


Description (diagnostics are in brown)

Fruit a dehiscent, 2-chambered silicle with 2–8 seeds per chamber, ovate or obovate to ± round in outline, strongly compressed perpendicular to the septum, (0.5)0.9–2 cm long x (0.5)0.7–1.5(2) cm wide, surface reticulately veined, apex deeply emarginate (notch ca. 5 mm deep), marginal wings broad throughout (1–1.5 mm wide basally, 3.5–5 mm wide apically). Stylar remnant 0.1–0.3 mm long, within apical notch.

Seed ± oval in outline, compressed, eccentric on one side (straight edge thickest), (1.2)1.6–2(2.3) mm long x 1.1–1.3(1.4) mm wide x 0.8–0.9 mm thick. Surface brown to blackish-brown, slightly shiny or iridescent, typically with a narrow groove extending ca. halfway up each face from the hilar notch, with several concentric granular ridges and transversely-lineated furrows.

Hilum in an exaggerated basal notch, often plugged with yellowish funicular remnant.

Embryo bent, cotyledons accumbent, endosperm lacking.

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)