﻿MR 



MIMOSEiE. 341 



mination of a single small specimen in the Berlin Herbarium, a San-Domingo species of 

 Mimosa, have the leaves reduced to single phyllodia. No peculiar connexion of the 

 phyllodia with any local circumstances has been observed. 



The simply instead of doubly pinnate foliage is, in the suborder, exclusively American, 

 and definitely characterizes a large genus {Inga including Affonsea), without any trace 

 of it in any other genus of American Mimosese, nor even in the nearest allied of Asiatic 

 forms, no passage from the one to the other either in the same species as in Gleditschia, 

 Ceratonia * or Moldenhauera, or in the different species of one genus as in Ccesalpinia^ 



thus raising the character to the rank of a good generic one. 



The general tendency of frutescent plants in stony deserts to degenerate into spincscent 

 scrubby almost leafless shrubs, is exemplified also in a few Mimoscrc, such as some 

 Acacice in AustraKa, Dichrostachys in Africa, Prosopis and Mimosa in extratropical 

 South America, but without exhibiting any thing of a genetic character. The develop- 

 ment, however, of prickles and of spinescent stipules appears to be influenced by grnrn- 

 logical as much as by physical causes. The prickles (aculei), wliotbcr scattered or in- 

 frastipular, are characteristic of groups of Fiptadenia, Mimosa (including SchranJda) 

 and Acacia J variously dispersed over America, Asia, and Africa, but have never found 

 their way into Australia, and are unknown in all other genera of Mimoseaj. When 

 hooked, they are particularly developed in scandent species, which they aid in sup- 

 porting ; but there are scandent species in other genera which entirely dispense with 



their aid. 



There are three east-tropical Asiatic species of Alblzzia {A. Millettiiy A. rufa, and 

 A. pedicellata), a genus otherwise absolutely without thorns or prickles, in which, how- 

 ever, a peculiar hooked appendage is often developed under the leaf, which hardens into 

 a woody hook, and appears to partake more of the nature of a thorn than of an epidermal 

 prickle, although its position bears no relation to any more developed organ in any other 

 Mimosea, the infrafoliar prickles of a few species of Mexican or of African Acacia are, 

 like the infrastipular ones, strictly epidermal. The species bearing these hooks are not 

 reported as climbers, and are sometimes noted as arborescent ; no^ such hooks are known 

 in any other Mimosea ; and the circumstances favouring their mamtenance m these very 

 few species, only observed in South China, Malacca, and Java, are as yet entirely 



""tpTnrcent stipules are met with in various groups, especially in the W'^ Gnmmifer^ 

 ^JFulcnell<B. and a few Fhyllodme<,. in a very few Call^andra^ and mkecol^ha, never 

 in Mimosa, AMzzia, Inga, nor in the smaller genera, and as far as has been obse. v^ are 

 always independent of physical conaions. These spmescent stipules m the A..c^^ 

 ^ ^ , ,, « \ ^„- «l Amprica Africa, or Asia, offer the curious pheco- 



Gmnmifer^, whether from f"? "T^^; j^'„f t^, p^,, or sometimes of nearly aU 



menon of an erfraordmary f f "P-^'^/^X ^Z Im ike enlargements are most 



of them, assuming the aspect of hor^ ^f -«^^^^.„„ ^, eoUector.°«m he relied on. 

 general in dry hot regions; hut as fa^jte"^ ^^^^ forest-regions of 



many of the ^V^^^^^^ ^^.^^ the .hole of the stipules .fly one 

 tropical America. They never appt^ ,o,4.M.rch. 



* 



See Pasquale, Eenfe K. Accad. Sc. Kapl- 18"". ""*■ 



