﻿MR. G. BENTHAM ON THE MIMOSE.E. ^ 351 



« 



In considering the data supplied by tlie above tables, the most striking feature is the 

 great American predominance not only of the whole order, but, if we deduct those 

 Australian and African Acacite which have less of a tropical character or are quite 

 extratropical, of every tribe and of the great majority of the genera and principal sub- 

 genera. Fiptadenla, Frosopis, Mimosa, two sections of Acacia, five sections of Pithe- 

 colobium, and Inga, with a few of their minor satellites, show each a lar pje number of 



American species, mostly of a comparatively extended area and rich in varieties ; whilst 

 Asia has only Albizzia, one section {Clypearia) of Fithecolobium, and in a less degree 

 two sections of Acacia, exhibiting the same character; and Africa is still further 

 deprived of Clypearia. 



This high degree of recent luxuriance and prosperity of American races, however, can 

 by no means be relied upon as evidence as to local origin, or even as to comparative^ 

 remoteness of antiquity ; for that may rather be sought for where there are the greatest 

 number of highly differentiated monotypes or oligotypes of limited areas and AxcmI 

 characters, exhibiting the last remains, as it were, of expiring races; and these arc 

 undoubtedly to be met with chiefly in the Old World, in the first place in East Africa 

 and the Mascarene Islands, and secondly in the Malayan archipelago. But this 

 question of what might have been the original birthplace of Mimoseae is involved in too 

 much obscurity, and the few conjectures that might be hazarded are connected with too 

 great a variety of disputed geological conditions and histories to be here discussed. It 

 may suffice to observe that there is qyqyy reason to suppose that the seven tribes, and a 

 few at least of the genera or subgenera, had been differentiated and spread over the 



g^-UCJ-Cl. WX kJW-^^j^ 



common area whence the tropical floras of America and Africa had been derived, for a 

 sufficient time before its disruption or disappearance to allow of their being all com- 

 municated to both the regions now so widely dissevered. A few words may also be 

 devoted to the consideration of how the several races have subsequently prospered in 

 each of the hemispheres, as far as can be judged of by the present aspect of what still 



Of the several races which have entirely perished m the one or the other 



survives. 



hemisphere, the records are, I beHeye, as yet too few and imperfect to form the basis 



of any satisfactory conclusions. . . „ . ^ /. » . 



Pentacleara is monotypic in hoth hemispheres, inhahitrng the moist forest regjons of 



North Brazil and Guiana in America, and of west tropical Africa « the Old World. 

 The two species are in the present day generically isolated and specifically distinct 

 Neither of them shows any tendency to yariahility, nor to any extension of area : and 

 both may be set down as expiring races. They may also he connected in tlioir or,s,„ 

 rather more with Ca^salpinc^ (Dimorphandrea,) than wi h Mimosc=a and perhaps with 



some of those races which, like Cassi. (Fict^e), had long left ^^t Is nurelv Z^ 

 . ,. Tf +]^g nearest connexion, Dimorphandra, is purely Ame- 



in Africa, and m Austraha. I the ^^ ^^^^^.^ 



ncan, the next step. ^^'^''^^^^^ncterTf Fentacmra. but more extended. It is 



Parkia has the S^-'S^f .'^^^jt^^ie com^non stock of C«salpinieee and Mimose». 



another of the old ^l^^^Z^Z^, in the moist forest regions of ,K>th 



: Z\ri m?W : It Has produced some . or 5 species in the Malayan 



VOL. XXX. 



