94, 95.] 



MORPHOLOGY OF THE LEAF. 



Ill 



acterized by the frequent reunion or inosculation of 

 its numerously branching veins, so as to form a kind 

 of irregular net-work. 



310 



Varieties of venation . 307, Feather-veined, leaf of Betula populifolia (White Birch), lying upon a leaf 

 of Plum-tree ; same venation with different outlines. 3 8, Palmate- veined, leaf of White Maple, con- 

 trasted with leaf of Cercis Canadensis. 309, Parallel venation, plant of "three-leaved Solomon's seal" 

 (Smilacina trifoliata). 310, Forked venation, Climbing Fern (Lygodium). 



Parallel-veined, as in the MONOCOTYLEDONS (called 

 also ENDOGENS). The veins, whether straight or curved, 

 ran parallel, or side by side, to the apex of the leaf or 

 to the margin, and are connected by simple transverse 

 veinlets hardly seen. 



Fork-veined, as in the Ferns (and other CRYPTOGAMS 

 where veins are present at all). Here the veins divide 

 and subdivide in a forked manner, and do not reunite. 



285. Of the Reticulate venation the student should 

 carefully note three leading forms : viz., The Feather- 

 veined (pinni-veined) leaf is that in which the venation 

 consists of a midvein giving off at intervals lateral 

 veinlets and branching veinulets, as in the leaf of 



