32 



sys'n':MAri(' poMoi.oc.y 



b. c. a 



jind Wciillliy Imvc stilV ri<ri(l Icmvcs, lliosc of Oj-iiiics and Fall 

 IMppin ai'c t liin and ]>lial>l('. 



In the strawlx'rry, lar<2:c leaves and vi^or aic nsually corre- 

 lated. Thick leaves are desirai)le in varieties of strawberries 

 becans(^ they are neither hadly torn by wind nor scorched by the 

 snn. The thin leaves of European grapes and strawberries 

 usually sulVer in the scorching suns of the New World. 



50. Simple and compound leaves. — 

 When the divisions of the blade do not 

 reach the midrib, a leaf is said to be 

 simple. The leaves of nearly all hardy 

 fruits are simple. When the blade 

 consists of two or more separate pieces, 

 appears to have several distinct blades, 

 each with a stalklet of its own, the leaf 

 is canipmind and each separate part is 

 called a leaflet. AVhen the leaves are 

 arranged on the sides of the main leaf- 

 stalk, a compound leaf is said to be pin- 

 nate; w^hen the leaves are all borne on 

 the tip of the leaf-stalk the compound 

 leaf is palmate. ]\Iost of the bramble 

 fruits have pinnately compound leaves ; 

 Sorbus, a little known tree-fruit has pinnately compound leaves ; 

 and the strawberry has palmately compound leav^es (Figs. 

 16-21). 



51. Outlines of leaf -margins. — Technically the edge of the 

 leaf -blade is the margin. It is said to be entire when completely 

 filled out ; serrate or saw-toothed w'hen cut into sharp teeth w^hich 

 point forward; dentate or toothed when the teeth point outward 

 and not forward ; crenate when the teeth are broad and rounded ; 

 undulate or wxivy when the margin forms a wavy line; sinuate 

 when the margin turns strongly inward and outw^ard; incised 

 when cut into sharp, deep, irregular teeth ; lohed when cut about 

 halfway to the midrib ; cleft when cut more than half way to 

 the midrib. In studying margins, serrations and other marginal 

 markings are most typical in the middle of the sides of leaves, 

 those at the base and apex often being crowded or lacking 

 (Figs. 16-22). 



Fig. 22. Leaf margins 

 crenate ; b. toothed 

 serrate : d. entire. 



