n.] 



MIMOSiE. 



43 



of several kinds of Acacia, it is sometimes dif- 

 ficult to recoornise them till they have attained 



Fig. 17- — The Bi-pixnate leaf of an Acacia. 



a considerable age. The stipules of the leaves, 

 (which are to ordinar}' leaves what bracts are 

 to flowers,) are in Acacia armdta converted into 

 spines, as shown at e. In some kinds of Acacia 

 the true leaves, with the petioles in their natural 

 state, (see Jig. 17,) are retained in the adult 

 plants, as in Acacia dealhata ; and in others, the 

 bi-pinnate leaves are occasionally found attached 

 to the phyllodia, as in A. melanoxylon. The 

 bi-pinnate leaves are composed of from six to 

 twenty pairs of pinnse, or compound leaflets (see 

 fmfig. 17), each of which consists of from eight 

 to forty pairs of small leaflets (cj). The Gum 

 Arabic tree, Acacia vera^ has leaves with only 

 two pairs of pinnae, but each has eight or ten 

 pairs of small leaflets. The branches and spines 

 are red, and the heads of flowers are yellow. 



