98.] 



MORPHOLOGY OF THE LEAF. 



115 



relative development of the intervening tissue. The 

 prefix pinnate is obviously used in contrast with 

 palmate among palmate-veined forms. 



293. Pinnatifid (pinna, feather, findo, to cleave), 

 feather-cleft, the tissue somewhat sharply cleft between 

 the veinlets about half-way to the midvein, forming 

 oblong segments. When the segments of a pinnatifid 

 leaf are pointed and curved backward, it becomes run- 

 cinate, i. e., re-uncinate (346). When the terminal seg- 

 ment of a pinnatifid leaf is orbicular in figure and 

 larger than any other, presenting the form of the 

 ancient lyre, the form is termed lyrate (340). 



342 339 338 340 



Feather -veined leaves, approaching the compound. 338, Quercus imbricaria undulate. 339, Q. alba 

 (White Oak') lobate-sinuate. 340, Q. macrocarpa lyrate. 341, Mulgedium (Milkweed). 342, Bipinnatifld 

 leaf of Ambrosia artemisifolia (Hogweed). 



294. Pinnately parted implies that the incisions are 

 deeper than pinnatifid, nearly reaching the midvein. 

 In either case the leaf is said to be sinuate when the 

 incisions (sinuses) as well as the segments are rounded 

 and flowing in outline. Such segments are lobes, and 

 the leaves lobate or lobed, a very generic term. 



295. Palmate forms. The palmate venation pre- 

 sents us with a set of forms which are, in general, 



