BUDS AND LEAVES. 



21 



their leaflets in pairs; unequally pinnate (Fig. 30) when they have 

 them in pairs surmounted by an odd terminal one. 



But often the division of pinnately compound leaves is carried still 

 farther, and the place of the leaflet is taken by another petiole bearing 

 leaflets ; the leaf is then termed bi- pinnate (Fig. 31) ; a step farther still, 

 and it becomes trrpinnate. In these cases the primary divisions are 

 termed pinnae, the secondary pinnules, though the blades are always 

 called leaflets. 



FIG. 29. Simple leaf of bass-wood. 



FIG. 30. Compound leaf of locust (Robinia 

 Pseudacaia). Unequally pinnate, the separate 

 blades (leaflets) being in pairs, with an odd terminal 

 one. 



Palmately compound leaves are also frequently divided and subdivided 

 in like manner, and may become bi- or tri-palmate, ternate, etc. 

 When the subdivision is carried to an extreme point the leaf is termed 

 decompound. 



The same terms are used in the characterization of the general outline 

 of compound leaves and their leaflets and the marginal f eatures of the lat- 

 ter as are applied to simple leaves. 



