44 BRITISH BOTANY. 



deeply cordate at the base, and clasping the stem. Flowers in 

 dense clusters, the expanded blossoms higher than the unexpanded 

 buds. Sepals spreading. Pods spreading, ascending, with several 

 fiexuous nerves. 



This plant is very common on the Surrey side of the Thames, 

 especially about Kew, Mortlake, and Putney. Annual or bien- 

 nial ; April, or rather May, to July or August. 



B. Napus, Lin. Rape or Coleseed. — e.b. 2146. l.b.s. 115. 



A. 18. C. 70. Lat. 50-59°. Alt. 0-200 yds. Tern. 51-46°. 



Stem and lower leaves as in B. Rapa ; upper leaves oblong, 

 narrowed below with a dilated cordate clasping base. Flowers 

 distant when they are expanding. The sepals and fruit are as in 

 B. Rapa. Mr. Babington truly says it is difficult to find any cha- 

 racter by which to distinguish this plant from the preceding. It 

 is often cultivated, like tares, for spring food, and it, like B. Rapa, 

 is occasionally seen in cornfields ; but we have never seen it na- 

 turalized, as the other is. 



In fields, only subspontaneous. Annual or biennial ; May- 

 July. 



B. nigra, Koch. Black Mustard. — e.b. 969. Sinapis nigra, 

 Lin. L.B.S. 118. 



A. 14. C. 50. Lat. 51-56°. Alt. 0-100 yds. Tern. 52-48°. 



Stems erect, robust, bristly or tubercular, round, glaucous, 

 branched, leafy. Root and lower leaves rough, lyrate-pinnatifid, 

 with a large terminal more or less sinuated lobe; the upper leaves 

 lanceolate, tapering at both ends, glabrous, or nearly so. Flowers 

 contiguous at the summit of the stem, as branches. Sepals spread- 

 ing. Pods erect, closely applied to the stem, oblong-linear, four- 

 angled, with a cylindrical short beak. 



On waste grounds, banks, and similar places. Annual ; June- 

 August. This plant varies both in its foliage and in its fruit. 

 Specimens have been collected on rubbish about Battersea and 

 Wandsworth with pinnate radical leaves, or pinnatifid, not lyrate 

 leaves. In these varieties the leaves are rather more glabrous, 

 and the pods are more compressed (flatter) than in the commoner 

 form, and they are rather patent-erect than appressed. Another 

 form has been observed with very turgid, quadrangular, closely 

 appressed pods, and with rougher herbage. 



Sinapis, Lin. — Annual, biennial, or perennial plants, with 



