286 FIELD AND WOODLAND PLANTS 



of most parts of Britain, flowering from June to September. It is a 

 very variable plant, quite smooth, and of a delicate, pale green colour. 

 Its stem varies from six inches to over two feet in length, sometimes 

 erect, with spreading branches, l)ut often climbing among the 

 neighbouring vegetation, supported by the twisted leaf-stalks. The 

 leaves are pinnately divided into stalked leaflets which are further 

 cut into three-lobed segments ; and the flowers are in racemes that 

 are either terminal or opposite the leaves. At first the racemes 

 are short, but they lengthen out considerably as upper flowers open 

 and the lower ones fruit. Each flower has a short pedicel that arises 

 from the axil of a whitish or coloured bract ; and the two small 

 sepals are either white or coloured like the bracts. The corolla is 

 oblong, tubular, formed of four petals in two pairs, with a short, 

 blunt spur at the base ; and its colour is very variable— usually 

 cream-coloured or pink, and often tipi:)cd with crimson. 



Some of the Mustards are very common weeds in corn-fields. 

 They belong to the genus Brassica, of the order Cruciferce, and are 

 distinguished by their long sUiquas, almost cylindrical in form, 

 terminating in a ' beak ' which is formed entkely of the persistent 

 style, or of this together with a modified portion of the fruit con- 

 taining one or more seeds. 



One of the commonest of these is the Wild Mustard or Charlock 

 (Brassica arvensis or B. Sinapis), a very abundant weed in most 

 cultivated fields, probably introduced originally from South Europe. 

 It is a very coarse plant, with scattered, bristlj', spreading hairs, 

 growing from one to two feet liigh, and bearing racemes of yellow 

 flowers that generally exceed a diameter of half an inch. The 

 leaves are ovate, with short, stift" haii's ; all are pinnately lobed, 

 and the lower ones have generally a large oval lobe, with coarsely- 

 toothed segments, and a few narrower segments along the stalk. 

 The fruits are spreading, many-angled pods, usually about an inch 

 in length, constricted between the seeds when ripe, with a beak 

 about a third the length of the \\hole pod enclosing a single seed 

 at its base. The plant flowers from JMay to August. 



The White Mustard (Brassica alba or Sinapis alba) is not so 

 common ; but it is somewhat largely cultivated for its seedlings, 

 which are used, with those of cress, as salad ; and tlie plant is not 

 unfrequently found as a weed in corn-fields and on otiier cultivated 

 ground. The whole plant is clothed with rather stiil hahs that are 

 directed downwards, and its height varies from one to two feet. Its 

 leaves are pinnately divided into ovate, coarsely -toothed segments, 



