164 



BUDS AND LEAVES 



nately compound, as in mountain ash. When a pinnately 

 compound leaf ends in a pair of leaflets it is even-pinnate, 

 as in black locust ; when it ends in one leaflet it is odd-pinnate, 

 as in sumac. In yellow sweet clover there are only three 

 leaflets ; in the black locust there are sometimes twenty-two 

 leaflets. In sweet pea the pinnately compound leaf ends in 



FIG. 99. Leaf Arrangement. 1, Alternate, wild cherry (Prunus serotina) ; 

 2, opposite viburnum (Viburnum acerifolium) ; 3, whorled, yellow field lily 

 (Lilium canadense) ; 4, fascicled, white pine (Pinus strobus) . 



tendrils. When the leaflets are arranged at the end of the 

 petiole the leaf is palmately compound; the number of leaflets 

 varies from three, as in gold thread and red clover, to eleven, 

 as in the palmately compound leaf of lupine. 



Forms of Venation. A leaf is parallel wined when the veins 

 run in the same general direction. Leaves in which parallel 



