BUDS AND LEAVES. 



19 



outstretcliod hand or the toes of a l)ir 1 ; hence such leaves are said to bo 

 palmately, digitately, or pedately veined. Thv leaves of the maplo, 

 Kjcanioro, and Ci.stoi-oil plant (Fij,'. 27) will nerve as illustrations. 



Between these two widely dillerent forms of venation in exogenous 

 plants are other connecting ones, as when a leaf has both a mid-vein with 

 more or less strongly marked lateral branches and largo diverging, palmate 

 ])ranches also. 



Again, upon the venation of loaves depends, to a very great extent, thoir 

 lOarginal sliai)e. In parallel-vcincd leaves the niargui is commonly entire 

 — that is, not notched or indented ; the common grasses, cat-tails, and 

 iris are familiar examples. In verj' many feather-veined leaves the mai-gin 



I 



FlO. 28.— Marftinal sliajjes of leaves. Beginning at the right, tlic first is sorrtito, Bccond dcntnte, third be- 

 tween dentate nnd crenatc, fourth cronate, fifth sinuate-toothed, sixth sinuate. ' Traced from nature, 



is also entire, as for example the magnolias, laurel, and flowering dogwood, 

 but more commonly they are variously notched or indented. Leaf mar- 

 gins so indented are characterized in botanical descriptions by technical 

 terms which ai'o, for the most part, self-explanatory ; as for example (Fig. 

 28), serrate, saw-toothed ; dentate, toothed, but with teeth less regular 

 than the preceding, and not pointing forward like them ; crenate, scal- 

 loped ; repand, undulate, or wavy, when the margin makes a wavy 

 line; sinuate, more strongly wavy or sinuous; incised, cut, jagged, 

 etc. Again, when the margin is deeply cut into a definite number of di- 

 visions, the leaf is said to be lobed, as throe-Iohed, fice-luhcd, or sseven-lobed. 

 When cut more deeply than half way to the centre or base, the leaf is said 

 to be cleft, and hence the terms ihree-clcft, Jive-deft, or trifld, qui7iquefid. 



