SPECIFIC DISTINCTIONS, 



461 



Aculei are remarkable in Rubus. 

 Spines in Prunus,' 



Bractem in FuMARiA,...DRACocEPHALON,...and the Indian spe- 

 cies of Hebysarum ; to which must he added the Coma, which is 

 a bushy head, composed of bractecc, that are of a large size, and 

 terminate the stem in Corona Imperialis,... Lavandula,. ..and 

 Salvia. 



Glandules furnish the essential mark in Pad(js,....Urena,... Mi- 

 mosa,... Cassia, and many other genera, which it would be im- 

 possible to distinguish without being acquainted with this part. 

 They are found on the serratures, at the base of the leaves, in 

 HELiocARPUS,...SALix,...and Amygdalus ;..iOn the back of the 

 leaves in Pad us,, ... U re n a, ...and Passielora ;...and on the aculei 

 in Bauhinia Aculeata, where by the apex of the aculei a liquor 

 is secreted. The Amygdalus is distinguished from Persic a only 

 by the glandules of the serratures ; nor could the species of 

 Urena be ever fixed without examining the glandules of the 

 leaves. The Convolvulus with a tuberculate calyx, is so varia- 

 ble in the shape of its leaves, that it seems divisible into many 

 species, yet it is kept together by the glandules: and there h a 

 species of Monarda, distinguishable from its congeners, by the 

 glandules, that are sprinkled over the corolla. 



Stipulje are of great consequence in many extensive genera, 

 where the species are .liable to confusion. Thus in one species 

 of Melianthus the stipule are solitary ;.. .in the other they are in 

 pairs and the Cassia Auriculata is rendered distinct from all 

 its congeners, by the shape of its stipidce, which are reniform 

 and barbate. 



Hybernacles afford likewise a certain specific difference. 



That gems or buds often differ greatly in the same genus, is 

 proved by Rhamnus ; in which the various species, viz. Cervi- 

 spina,... Alaternus,... Paliurus,... and Frangula, have all a 

 difference in their buds ; and in that extensive and intricate ge- 

 nus, the Salix, the species are, by the structure and foliation 

 of the buds, distinguished with great certainty. 



Bulbs also distinguish the species, as is proved by Scilla, where 



