224 Plants and their Ways in South Africa 



II. 



explode and scatter their seeds. Sutherlandia has inflated 

 pods which catch the wind. The pods of Medicago are 



furnished with hooks, which 

 catch hold of the passer-by 

 and get free rides. 



Inflorescence a raceme. 

 The order is divided into 

 three groups or sub-orders. 



Mimoseae. — Flowers regular. 

 Corolla valvate. Stamens many. 



Caesalpineae. — Flowers irregular, 

 back petal folded within the side 

 petals, which are overlapped by the 

 front petals. Stamens lo or fewer. 



Papilionaceae. — Flowers irregu- 

 lar, back petal (standard) folding 

 over the side petals (wings or alse). 

 The side petals overlap the two front 

 petals, which join to form the keel. 

 Stamens 10. 



In some flowers of this 

 group the stamens and pistil 

 are held in the keel, and are 

 released with an explosion, 

 as in Lidigofera^ so that only 

 one visit of the bee is in- 

 vited. In the sweet pea, a 

 brush on the style sweeps the 

 pollen out of the keel. In 

 the bean and Snail Creeper 

 the stigma is forced out when 

 the bee presses down upon 

 the wings, and returns when 



Fig. 221.— Floral diagrams of Leguminoseae, . i i. • 



showing folding of sepals and petals in it llieS away, SO that the 066 IS 

 I. Miniosese ; II. Caesalpineae; III. Pa- . .^ , , ,, 



piiicnacejE. invitcd repeatedly. 



III. 



Sub-tribe Mimose^. 

 Acacia. — The minute flowers are clustered in golden 



