THE FORMS OF LEA I'ES 



45 



54. Other type forms are the elliptical, which 

 is like the oblong, except that it tapers equally 

 both ways from the middle ; spatulate, which 

 is oblong with the lower end narrow; oval, which 

 is broadly elliptical ; orbicular, circular in outline ; 

 deltoid, or triangular ; cuneate, or wedge-shaped ; 



linear, or several times longer 

 than broad, and the same width 

 throughout; needle-shaped, as in 

 pines and spruces. If any of 

 the type forms are reversed, 

 or inverted, the fact is ex- 

 pressed by the prefix ol> ; as 

 oblanceolate, obovate. Combi- 

 nations of these terms, together 

 with the use of familiar adjec- 

 tives (as short-ovate, long-lan- 

 ceolate , round - obovate , etc . ) , 

 express most of the common 

 outlines of leaves. 



55. Aside from the general outline, the form 

 of the leaf is determined by the shape of its 

 apex and base. The apex may be acute or end- 

 ing in a sharp angle (Figs. 24, 25, 37) ; acuminate, 

 ending in a long point (Figs. 26, 38) ; obtuse, or 

 blunt (Fig. 19) ; truncate, or squared at the end ; 

 retuse, or indented (as the upper leaves in honey- 

 suckle). The base may be cordate or heart-shaped 



FIG. 39. 



Cordate-ovate crenate leaf 

 of catnip. 



