166 BRITISH FLOWERING PLANTS chap. 



HiPPOCREPIS 



H. comosa (Horse-shoe Vetch) takes its name from 

 the shape of the joints of the seed-pod. The pod forms 

 almost a complete circle, the con- 

 cave margin of which is continuous, 

 while the convex side is thrown into 

 abrupt undulations (Fig. 109). It 

 might have been supposed that the 

 pod would break up at the narrowest 

 parts. As a matter of fact, how- 

 FiG. i09.-Frmt of mppo- ^-^ j-^gg q£ dehiscence are 



orepis. ' c 1 1 • T 



in the centre oi the thickest parts, 

 so that the detached portions have the forms of horse- 

 shoes. Each segment would normally include two seeds, 

 but as a rule one is aborted. 



Anthyllis 



A. Vulneraria is our only representative of this genus, 

 which contains about twenty species, distributed through 

 the north temperate region of the Old World. It agrees 

 with Lotus in its general arrangement. The tube of the 

 flower is, however, elongated ; and in consequence this 

 species is only visited by bees with long tongues. In 

 the young flower, though the pistil is in the keel, and 

 necessarily in contact with the pollen, H. Mliller has 

 observed that the stigma is dry, and that pollen which 

 falls on it is easily shaken ofl". Subsequently, however, 

 when most, or all, of the pollen has been removed, the 

 stigma becomes sticky, and pollen adheres closely to it. 

 The pollen grains are short six-sided prisms with striated 

 angles. The dried and swollen calyx helps the disper- 

 sion of the fruit. The whole plant is covered with short, 

 appressed silky hairs. 



ViciA (Vetch) 



The Vetches (Vicia) are distinguished from the Peas 

 (Lathyrus) by having the style filiform or angular, and 



