Mapping remains tentative, and some uncertain records (open dots) may be transferred to the true B. rapa; see notes under that name. B. napus is a variable annual that is widely cultivated in cool temperate regions of North America, and often escapes. It includes var. napus, which is the widely cultivated "rape" (also known as "canola oil seed"), and var. napobrassica (L.) Peterm., which is the "rutabaga"; 2n = 38 (Al-Shehbaz 1985). B. napus was not recorded as a wild plant in Ky. until the 1960s (M). Almost all records are referable to var. napus, but var. napobrassica has been collected in a wild context from OLDH (DHL). B. napus may have hybrid origin from B. sylvestris L. (2n = 18), which is also the progenitor of B. oleracea L. (including cabbage and kale) and B. rapa L., (including turnip) with which there has been some confusion. These cultivars have become important for human nutrition; there is also growing evidence for prevention of cancers by their diverse glucosinolates and especially S-methyl cysteine sulphoxide (e.g. Edmands et al. 2013). Rabbits (at least European) can also feed heavily on these plants, with little or no ill-effects (e.g. Boag et al. 1990). However, cattle, sheep (to a lesser extent) and other ruminants can suffer serious anaemia or other problems after excessive feeding on them (e.g. Smith 1978, Arnold & Lehmkuhler 2014).