LEGTJMIN0S2E-MIM0SE2E. 49 



including about eleven hundred species, presents so many constant 

 characters that to subdivide it we must fall back upon features 

 which are elsewhere deemed of wholly secondary value. Thus we 

 have seen that the genera are mainly based on the form and de- 

 hiscence of the fruits and the relations of the endocarp to the seeds, 

 and the degree of complexity of the leaves, which are either simply 

 pinnate or bipinnate. The series or tribes are based on the prae- 

 floration of the calyx, the number of stamens, and the presence or 

 absence of a sort of glandular prominence on top of their connectives. 

 Hence we get the four following series, which alone do we retain : — 



I. Adenanthere^i. — Calyx valvate; androceum diplostemonous ; 

 stamens free, usually 1 tipped by a gland. 



II. Eumimose.e. — Calyx valvate ; androceum isostemonous or 

 diplostemonous ; stamens free, without apical glands. 



III. Parkier, — Calyx imbricate; androceum diplostemonous or 

 pleiostemonous, with only five fertile stamens ; apical glands present 

 or absent. 



IV. AcaciEjE. — Calyx valvate; stamens indefinite, free, mona- 

 delphous or polyadelphous. 2 



The Mimosca are plants from warm climates, abounding in the 

 tropical and subtropical zones of both hemispheres, and hardly 

 extending more than forty degrees on either side of the Equator. Of 

 the twenty-eight genera retained by us, five alone are peculiar to 

 America, viz., Plat/i/jmenia, Stri/pJaiodendron, Lysiloma, Enterolobium, 

 and Affonsea ; and eight to the Old World — viz., Pentaclethra, Me- 

 phantorrhiza, Gagnebina, Tefraplcura, Xerocladia, Serianthes, Xylia 

 and Archidendron. Of these last the five former have only been 

 observed in tropical Africa or Madagascar ; the three latter in Asia 

 or Oceania. Archidendron, a monotypical genus, is only Australian ; 

 but the genera found in nearly every warm climate are very unevenly 

 distributed as a rule. Thus, Mimosa, Calliandra, Pithecolodium, and 

 Acacia have species in all the countries of the world, but Calliandra, 

 out of eighty species, has only one in the Old World. Those of 



1 This gland is almost entirely absent in one 2 The freedom or union of the stamiual fila- 



section of the genus Prosopis. In Xylia it may ments is used by BENTHAM to distinguish two 



disappear so early that until now its presence series, Acacicic ami Tngeee, whicb we are unable 



has not been recognised. toseparate for the reasons given above(pp. U, 12). 



VOL. 11. I 



