NATURAL ARRANGEMENT. 



511 



Mutis says, is obtained from Myrosp^rmum peruiferum, and the balsam of Tolu from M. toluiferum ; the 

 Cachou, which has been found to be almost pure tannin ; and which is supposed to be produced by Acacia 

 Catechu ; of the same character is that remarkable resin that is yielded by Hymen^ v Cotirbaril ; gum Arabic, 

 produced by the bark and roots of /Ickcia vera, Senegal, arabica, and others ; gum tragacanth obtained from 

 Astragalus creticus, gummifer, and verus ; and finally, manna, secreted by Alhugi Maurorum." Cuttings 

 and seeds ; some by division. 



The arrangement of this tribe of plants has been found to be attended with much difficulty. By Limifeus, 

 and the writers who succeeded him, the number of genera was much smaller than those admitted by botanists 

 of the present age ; many additions have been made in consequence of the discovery of New Holland, and a 

 large number of subdivisions in old genera have been from time to time introduced by one writer or another. 

 To combine these scattered improvements under one uniform system has lately been attempted by the learned 

 botanist, from whom the foregoing extract has been taken. M Decandolle's method being here adopted, 

 it will be useful to explain the principles upon which it is founded. He divides Leguminosa? into two grand 

 divisions, the first of which consists of plants the radicle of whose seed is curved back upon the edge of the 

 cotyledons, and the second of those whose radicle and cotyledons are straight : the former are CURVE'MBRIJE, 

 the latter KBCTO / MBXl4fc, Tn the Curve'mbri<e, certain diversities in the structure of the calyx and corolla again 

 divide into two principal forms : one of which, comprehending all the genera with papilionaceous flowers, 

 is called Papilion'icea? ; and the other, consisting of a very small number of species, with one or two petals or 

 more, and an obscurely lobed calyx, is called Swartzie^a?. The last is not subdivided, but the Papilionacea? 

 resolve themselves into the two great tribes pointed out by M. Decandolle, namely, those with fleshy cotyle- 

 dons and eatable pulse, Sarcdloba: ; and those with foliacoous cotyledons and seeds which are not eatable, 

 Phylldlobce. Each of these is divisible by three, upon slight differences in the fructification. In Recttimbrice 

 two suborders, Mimosese and Cassalpineae, are formed upon variations in the aestivation of the calyx and 

 corolla; in the former, it is valvate, in the latter, imbricated; the first constitute a single tribe, the latter 

 divide into three, distinguished by less momentous peculiarities of structure. Having premised thus much, 

 the following tabular explanation will be intelligible : 



