NOMENCLATURE OF THE LEAF. 63 



d. Spine-pointed or cuspidate when it runs out gradually into 

 a small awl-shaped rigid spine, as in thistles and poplar leaved 

 fig-tree. (F. 125.) 



e. Awned when it is terminated by a long rigid spine, which 

 does not appear as a continuation of the leaf. (F. 122.) 



f. Cirrose or circinate tipped withatendril. (F. 123.) Thisten- 

 dril is, in a few instances, furnished with an additional organ for 

 some particular purpose, not essential to the leaf; thus, in one 



_Apecies of the genus nepenthes, the apex of each leaf terminates in a 

 long rigid thread, a continuation of the midrib, bearing a small co- 

 vered pitcher, (F. 127) which is generally found nearly full of water. 

 In another species, this pitcher is sessile, (F.129); and in the dionrea 

 muscipula, or Venus's fly-trap, the appendage is composed of a pair 

 of toothed lobes. (F. 130.) 



g. Obtuse when it forms the segments of a circle, and is rounded, 

 as in broad-leaved dok and square-stalked St. John's wort. (F. 128.) 



h. Pointed-obtuse when a small point projects from the middle 

 of the obtuse apex. (F. 132.) 



i. Thickened when the rounded apex of a leaf is a little thick- 

 ened, but not sufficiently so as to render it clubbed. 



j. Retuse when it is obtuse, with a broad shallow notch in the 

 middle, as in common mountain sorrel. (F. 133.) 



k. Emarginate when the notch is sharper or nearly triangular, 

 as in bladder senna and common penny- wort. (F. 135.) 



1. Truncated when it appears as if cut across in a straight line, 

 as in the common tulip tree. ( F. 134.) 



m. Jagged or prsemorse jagged, pointed, as if bitten off; very 

 blunt, with various irregular notches, as in hibiscus pnemorsus. 

 (F. 136.) 



n. Tridentate when the apex forms three teeth, as in genista 

 tridentata. (F. 131.) 



17. Base: By some botanical writers, leaves are 

 described, from the nature of their bases, as being heart- 

 shaped, hastate, reniform, &c. but as these terms have 

 been explained under the superficial configuration of 

 leaves, there only remains to be observed, that leaves 

 may have an equal or an unequal base. 



