THE DICOTYLEDONES 167 



/3 



leaves. '^Fhere are some twenty species which are restricted to New^ Zealand 

 and Lord Howe Island. Biserrida pelecimis (Fig. 1532) produces pods which 

 superficially resemble caterpillars and are said to be picked up by birds in 

 mistake, whereby the seeds are distributed. 



Fig. 1532. — Biserrida pelecimis. Legumes re- 

 sembling caterpillars. 



The sub-family Hedysaroideae is also a large one, containing nearly 

 fifty genera, the majority of which are either tropical or subtropical plants. 

 A few occur in the Mediterranean region, temperate Asia and South 

 America. One of the most important genera is Arachis, of which there are 

 ten South American species. A. hypogaea is the Ground Nut or Pea-nut, 

 W'hich is now widely cultivated in the warmer parts of the w^orld, especially 

 in West and East Africa. The seeds are edible and when pressed yield one 

 of the oils w hich are used for the manufacture of margarine. The plant is 

 interesting in that the flowers after fertilization bend downwards, and, by 

 the elongation of the flower stalk, the young pod is thrust underground 

 where it ripens. 



Coronilla varta exhibits a pollination mechanism not unlike that in Lotus 

 corniailatus. The nectar is usually secreted on the outer surface of the 

 calyx although in some flowers it may be absent. All ten stamens are con- 

 cerned in pushing the pollen forward into the keel; moreover the pollen 

 grains are joined together in threads. The keel is not easily depressed. 

 Bees settling on the flower push about among the petals for the nectar and 

 effect cross-pollination. It is doubtful if self-pollination can take place. 



The Vicioideae are a small and remarkably uniform sub-family com- 

 prising only six genera and about 150 species. Two of these, Vicia and 

 Lathyrtis, are common in this country. Pisiim, with six species, is a native of 

 the Mediterranean and western Asia, and Lens, also with six species, is 

 similarly distributed. All the genera are of great economic importance, as 

 for example the Broad Bean, Via'a faba; the Garden Pea, Pisiim sativum 

 and Lens esculenta, largely cultivated in southern Europe and sold as the 

 Lentil. Cicer arietinum is the Chick Pea which is used for food in southern 

 Europe and India. The genus Abrus contains six tropical species, of which 



