THE PEA FAMILY. 



129 



s c 



A 



Sb 



the others, and there is no true " keel." The stamens 

 are irregular, being unequal (s.a. and s.b.), some being 

 reduced to staminodes (s.c). The fruit is a pod or 

 legume, as in the first sub- 

 order. ' 



Aca'cia. — This is a 

 good type of tlie third 

 sul)-order. The flowers 

 are minute, forming dense 

 yellow clusters ; they are 

 quite regular. The calyx 

 forms a little tube (Fig. 

 52, I.) ; the five petals 

 do not overlap, but just 

 meet by their edges, being 

 valvate (I.). The stamens 

 are numerous, and the sc 

 pistil forms the character- 5 b 

 istic legume common to 

 the whole family (Fig. 

 52, III.). 



The species consist of 



trees and shrubs ; the Fro- 51,— Cas'^m aracUVdes. I. Diagram 



of flower. II. Vertical section of flower ; 



majority have no leaf- "c'stamfnoder^"'' '^' '"^" «*^'^°^'^°s? 

 blades, but only petioles, 



which, however, are flattened in a vertical position, and 

 called pliyllodcs. The use of this, as stated with 

 regard to the sleep of plants (p. 4), is to avoid loss 



