﻿MR. G. BENTHAM ON THE MIMOSE^. ' 339 



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dehiscent in Calliandra, and in all the genera with albuminous seeds. The mode of 

 dehiscence gives sometimes rather more available generic characters; for it appears 

 to depend rather more upon internal structure. The obliquely elastic woody pods of 

 Te7itaclethra have been commented on by Oliver (Trans. Linn. Soc. xxiv. 415). The 

 elastic dehiscence of OalUandra neatly characterizes a large group which was at first 



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thought to be geographical as well as natural, having been supposed to be strictly limited 



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to the warmer regions of Ajnerica. Three or four species are now known to exist in 

 tropical Asia ; these, however, are all very distinct and but little-varying species, and all 

 of very limited area, and may be set down as in all probability old races in the course 

 of extinction, whilst the American races appear to be in the full vigour of life, mul- 

 tiplying, varying and spreading, with specific limits often as yet very ill-defined ; and in 

 future ages it may be expected that CaUlandra, with its elastically revolutc pod-valves 

 and other characters, may become a more and more distinctly natural as well as 

 geographical genus. A similar dehiscence, but accompanied l)y very difrcreut fioral 

 characters, is observable also in three species of Acacia (A. nigricans, A. ohsctira and 

 A. strigosa), forming a small distinct group, with a very limited range, in the neigh- 

 bourhood of King Greorge's Sound, in South-west Australia, and in two or throe northern 

 species of the phyllodineous group, all of them apparently very local ; the character is 

 otherwise, as far as known, strictly confined to the Calliandrce of the true American 



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type. 



The closely united nerve-like margins of the two valves, persistent after the remainder 

 has fallen away leaving a so-called replum, is eminently characteristic of the genera 

 Bntada, Mimosa (including Schrankia) and Zysiloma, and is not, as far as I am aware, 

 to be met with in any other genus. It is, therefore, perhaps the most important cha- 

 racter derivable from the fruit, and is almost always well marked when the pod can be 

 observed at or near maturity. It is only in one or two of the small thick-fruited speci.^ 

 of Mimosa that the margins appear sometimes to split with the valves at the apex of the 

 pod; and m Acacia Guachapelle, H., B. et K., which I have transferred with "- 

 hesitation to Lysiloma, this margin has appeared to me to remam quite consohdated on 



^1 . . \ 1 J ^^ +1.0 T^^f1 but to split With the valves on the inner ventral 



the exterior or dorsal edge of the poa, Dui lu bpnu ,. ^. - r *i • 



or semixnferous edge. This requires, however, further :nvcst:sation from perfectly npe 

 fruits, which have not been observed. The plant is. moreover an exceptzoaal oue. 



som<; 



a 



.' „ ^ M '^x. +1 « i.nT.,'f jiTifl flowers of the more onstern tropical American 



native of Guayaquil, with the habit ana nowtrs u ^ ,.,,., .., ,.# 



,.., , ,. L^ .... ...1 .f +T.. Asiatic JJJjizzia Lehbech both with very dif- 



JPlthecolobium Saman, and of_ the Asiatic 



ferent pods. ^ cpr^aration either of the whole pod or of its dccidtious 

 T>ia o^fiViilflfA vjilvfts — that is, the separauuu cit x 



distinct articles by 



TYiituritv into aistmci arueies ny a iransverse 



valves .dthiu the persistent ^^-f^^'^^X^ ^ „„ ,t,olute oharLr sufficient 

 M.Ac.'.r.^ i.^+«r^or. AnnTi f,wo secds, has often oeen oivrn u« 



division between each two 



non oeweeu^ouu -—— foom all others, however closely alUed in all other 

 parate geneneaUy smgle species trom a ^^ 



respects. This articulation is -ost maA^ ^ th m y^^ ^^ J^^^^ ^^^^^^ , 



is by no means constant e.her in ft -^ ';^f ^„,„^,i^t, ^^^^ U wholly disapVi 



into which It can be « jUs^^^^ ;,„,„,,„ j:,iie«los. or of JIMu^iu Acantko. 

 and even in some single species eiuier ui x> 



