FOLIAGE-LEAVES. 



115 



narrower than the base, and those in which the apex is 

 broader than the base. 



172. In the first of these three classes it is evident that 

 any variation in the outline will depend altogether on the 



Fig. 152. Fig. 153. Fig. 149. Fig. 150. Fig. 151. 



relation between the length and the breadth of the leaf. 



When the leaf is extremely narrow in comparison with its 



length, as in the Pine, it is acicular or 



needle-shaped (Fig. 145). As the width 



increases, we pass through the forms 



known as linear, oblong, oval, and 



finally orbicular, in which the width 



and length are nearly or quite equal 



(Fig. 146). 



Fig. 154. 



173. In the second class the different ^- 

 forms arise from the varying width of 

 the base of the leaf, and we thus have subulate or awl- 

 shaped (Fig. 147), lanceolate, ovate, and deltoid leaves 

 (Fig. 148). . 



Figs. 149 to 154. Various forms of foliage-leaves. 



