60 



MORPHOLOGY, OR COMPAEATIVE ANATOMY. 



Lobed Leaves. A very large number of simple leaves, and of leaflets 

 of compound leaves, are divided more deeply between the principal ribs; 

 to such the general name of lobed leaves is often applied, and the more or 

 less distinct parts are called lobes; thus we may nave hi lobed (tig. 89), 

 trilobed (tig. 90), and so on, according to the number of the divisions. 



Fig. t>\ Fig. 93. 



Fig. 89. A bilobed leaf. Fig. 01. A pinnatifld leaf. 



Fig. 90. A trilobed leaf. Fig. 92. A pinnatinartite leaf. 



Fig. 98. A pinnfttipartfte Tyrato !<>nf. 



But it is found requisite in Descriptive Botany to subdivide lobed 

 leaves into more definite classes ; of these there are two principal types. 

 defined by the character of the ribbini/. Wlu>n the ribs are arrauge'd on 

 the feathered plan, we first take the prefix pinnati- (feathered}, and sub- 

 join to this a word indicating the degree or kind of division, thus : pinna- 

 tifid (feather^cleffy, if the broad notches between the lobes extend from 

 the margin to about halfway between this and the midrib (fig. 91) ; 

 pinnatipartite, if the notches extend nearly to the midrib (tig. 92) ; pinna- 

 tiwt. if the separate lobes are almost free, and merely connected by a 

 narrow strip of parenchyma. Certain less frequent modifications of these 

 forms of the feathered type are conveniently distinguished by technical 

 terms, such as : sinuate, a form either of the pintiatifnl or pinnatiwt leaf, 

 when the excavations and the apices of the lobes are rounded, as in the 



Fig. 94. 



Fig. 95. 



A palmiflil leaf, the nine acute lobes 

 serrated. 



A p:ilmip:ir(ite letif. the five oblong 

 lobes uudulated. 



