TYPES OF LEAVES 



49 



attached aloi;g the margin of the petioles as in the clovers; 

 sometimes they are developed as sheaths enclosing the stem as 

 in the grasses and grains ; and sometimesi they enclose the young 

 leaves as in the tulip tree. 



Types of Leaves, — Leaves which have one prominent mid- 



1. — Palniately veined leaf 



Fig. 37. — Palmately veined leaf. 



rib running from base to apex, and giving rise to numerous side 

 branches with smaller veinations between them are said to be 

 net-veined (Fig. 34), while leaves which have a number of 

 equally prominent veins running from base to tip are said to 

 be parallel-veined. (Fig. 35.) Most dicotyledonous plants 

 have net-veined leaves, while most monocotyledonous plants 

 have parallel-veined leaves. Leaves which have three, five or 

 more prominent ribs or veins arising from a common point are 

 said to be palmate-net-veined or radiate-net-veined (Figs. 36 

 and 37), while those that have numerous veins arising from a 

 main mid-rib are said to be pinnate-net-veined or feather-net- 

 veined. (Fig. 34.) 



