FORM OR FIGURE. 



59 



forms, in which there is no distinction of petiole or blade. Such are the 

 acerose (needle-shaped) leaves of the pine, the subulate (awl-shaped) 

 and scale-form leaves of the cedars, etc. 



MARGIN. 

 The following terms apply to the various modifications of the margin, as such, 

 uot affecting the general outline of the leaf. 



a b c d 6 f g h 7c I 



154. Diagram of leaf-margins, a, entire; b, undulate; c, repand; tf, spinous; e, crenate; 

 / dentate; g, serrate; A, laciniate ; k, incised; /, erose. 



278. Entire, even edged, having the tissue completely filled out. 

 Sometimes a vein runs along the margin, which might otherwise be 

 easily torn, as in the Caladium. But when the marginal tissue is de- 

 ficient, the leaf becomes 



279. Dentate, having sharp teeth pointing outward from the centre; 

 serrate, with sharp teeth pointing forwards, like the teeth of a saw ; 

 crenate, with rounded or blunt teeth. The terms denticulate, serrulate^ 

 crenulate, denote finer indentations of the several kinds ; doubly den- 

 tate, &c, denote that the teeth are themselves toothed. 



280. The undulate, or wavy edge is somewhat different from the 

 repand, which bends like the margin of an umbrella. If the veins pro- 

 ject, and are tipped with spines, the leaf becomes spinous. 



281. Irregularly divided margins are said to be erose or jagged, 

 laciniate or torn, incised or cut. 



282. Crisped. Often, instead of a deficiency there is a superabun- 

 dance of marginal tissue, denoted by the term crispate or crisped. 



AP EX. 



a b e d e f 9 h k 



I » v ti • u o u p 



155, Apex of leaves, a, obcordate ; b, emarginato ; c, retuse ; d, truncate ; e, obtuse ;/, acute ; 

 ff, mucronate ; h, cuspidate ; k, acuminate. 



156. Bases of leaves. I, hastate ; m, n, 6aggittate ; o, auriculate ; p, cordate ; q, renlform. 



