Sinapis arvensis  (Brassica kaber) charlock Brassicaceae SIAR*;  R;

Sinapis arvensis.de.wikipedia.org

Sinapis arvensis.de.wikipedia.org (Accessed 4/2014).

Sinapis arvensis is an annual or winter annual herb, about 60 cm tall; from a overwintering rosette.

Leaves alternate, widest above middle, to 20 long, 10 cm wide, pinnately divided, terminal leaflet much larger than lower ones, leaves rough, hairy, lower leaves toothed to lobed, stem leaves reduced progressively upward. 

Flowers yellow, petals 4, to 1.2 cm long, widest near tip, tapering sharply to thin base (Uva et al. 1997), pollinated by bees and some flies, sometimes self-fertile (some autogamy), (Mulligan and Kevan 1973); blooming May-July. 

Fruit dry, linear capsules, about 1.5 cm long, 0.2 cm wide, with flattened beak about 0.7 cm long; seeds 7-13, ca 0.1 cm long. Seeds viable for many years in soil. 

Wetland status: NL. 

Frequency in NYC: Very infrequent. 

Origin: Europe, however may be a native plant used by various native people thousands of years before European colonization (Warwick et al. 2000). 

Habitat: Open areas, roadsides. Agricultural weed. 

Notes: Listed as a noxious weed in 46 states (USDA, NRCS 2010). Roots shown to contain antifungal compounds. Plants of the mustard family rarely form mycorrhizal associations (Warwick et al. 2000). Contains toxic mustard-oils (isothiocyanates). The most common of these is allyl isothiocyanate: CH2=CH-CH2–N=C=S. The nitrogen-carbon-sulfur group is the active component and gives mustards their sharp pungent taste but some of these chemicals, including allyl isothiocyanate are very toxic (Kingsbury 1964). Eaten by many insects including Lygus spp. (Hemiptera), Frankliniella spp. (Thysanoptera), Phyllotreta spp. (Chrysomelidae) and Pieris spp. (Lepidoptera). Sinapis arvensis is also parasitized by numerous fungi. It also is host to a number of viruses (Warwick et al. 2000).