256 BOTANY FOR BEGINNERS CHAP. 



Root. A branched tap-root with a large number of nodules on 

 the branches. These nodules are caused by bacteria (p. 132). 



Stem. Herbaceous, ribbed, solid, hairy, green. 



Leaves. Cauline, alternate, pinnately compound, stipulate ; 

 the stipules are large, green, and persist ; some of the leaflets 

 are converted into tendrils. 



Inflorescence. Axillary and two flowered. 



Flower. Complete, zygomorphic, papilionaceous ; diameter 

 one inch ; generally white in colour. 



Calyx. Gamosepalous ; 5 lobed ; perigynous ; green and 

 hairy. 



Corolla. Polypetalous ; 5 petals ; perigynous ; consists of a 

 standard, wings, and a keel. (p. 180). 



Andrcecium. Diadelphous ; 9+1 stamens ; perigynous ; the 

 single posterior stamen is free and the rest are united, having an 

 opening all along the posterior face as well as at the top of the 

 bundle. At the base of the inner row of stamens five nec- 

 taries occur. The honey formed by them accumulates between 

 the stamens and the base of the ovary. 



Gynoecium. Monocarpous ; superior ; parietal placentation. 



Fruit. A legume ; seeds exalbuminous. 



Pollination. The flowers of all the plants of this order are 

 adapted for insect pollination. The pea is generally pollinated 

 by the bee. The insect rests on the flower using the wings of 

 the flower as a platform ; its weight pulls these down and draws 

 the keel forward. The stamens, protected by the keel, thus come 

 in contact with the under side of the bee and dust it with pollen, 

 The bee now thrusts its tongue down the slit in the bundle of 

 stamens and sucks up the honey. As flower after flower is 

 visited, cross-pollination occurs. Self-pollination sometimes 

 takes place. 



Other Leguminous Plants. Trifolium repens (Dutch Clover) is a 

 creeping perennial. Each leaf is divided into three leaflets and at its 

 base there is a pair of small stipules. The flowers are in heads. 



Cytisus (Laburnum and Broom) possesses monadelphous stamens. 



Viciafaba (Broad Bean) possesses a strong erect stem. 



Phaseolus coccineus (Scarlet Runner) has a left-handed twinging stem 

 by means of which it climbs around slender supports. 



Properties of Leguminosae. Many are largely used in medicine ; 

 some are poisonous, others are largely cultivated for food. 



Laburnum. The seeds of Laburnum are poisonous. The plant can 



