Brassica rapa L.
Family: Brassicaceae
Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)
the most likely form found as a table grape
contaminant is probably the weedy ssp. sylvestris (L.) Janchen
Pertinent Common Names (particularly those used in California; go to GRIN for other common names)
wild turnip, field mustard
Primary Disseminule Type
seed
Description (diagnostics are in brown)
Fruit a dehiscent silique, terete, linear, constricted between seeds, glabrous, (2)3–8(11) cm long x (1.5)2–2.5(5 mm) wide including the apical beak (=terminal segment) which is 8–22 mm long, each of the 2 valvular segments with 8–15 seeds.
Seed ovoid (smooth to angular) to nearly globose, (1.1)1.5–2(3) mm diameter, with or without a distinct ridge or groove representing the position of the radicle. Surface glabrous, yellow or gray to reddish-brown or black, sometimes mottled, finely reticulated, interspaces of mature seeds typically pitted, interspaces and reticulum stigmaticose.
Hilar region a flush or slightly raised white linear ridge (not always present on yellow seeds) within a darker-colored (brown to black) circular area that is slightly convex.
Embryo bent, cotyledons conduplicate, endosperm lacking.
Similar Species
Similar Species Comparison Chart
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