SECTION 7. J 



ORDINARY LEAVES. 



59 



becomes thrice pinnate, or tripinnate, as iu many Acacias. The first divi- 

 sions are called Pinna ; the others, Pinnules ; and the last, or little blades 

 themselves, Leaflets. 



155. So the palmate leaf, if again 

 compounded in the same way, be- 

 comes twice palmate, or, as we say 

 when the divisions are in threes, 

 twice ternate (in Latin form biter- 

 nate) ; if a third time compounded, 

 thrice ternate or triternate. But 

 if the division goes still further, 

 or if the degree is variable, we 

 simply say that the leaf is decom- 

 pound ; either palmately or piu- 

 nately decompound, as the case 

 may be. Thus, Fig. 161 repre- 

 sents a four times ternately com- 

 pound (in other words a ternately 

 decompound) leaf of a common 

 Meadow Rue. 



156. When the botanist, in de- 

 scribing leaves, wishes to express 

 the number of the leaflets, he 

 may use terms like these : 



Unifoliolate, for a compound 

 leaf of a single leaflet ; from the 

 Latin utium, one, and foliolum, 

 leaflet. 



Bifoliolate, of two leaflets, from the Latin bis, twice, and foliolum, leaflet. 



Trifoliolate (or ternats), of three leaf- 

 lets, as the Clover ; and so on. 



Palmatelj/ bifoliolate, trifoliolate, 

 quadrifoliate, plurifoliolate (of several 

 leaflets), etc. : or else 



Pinnately bi-, tri-, quadri-, or pluri- 

 foliolate (that is, of two, three, four, 

 y five, or several leaflets), as the case 

 may be : these are terse ways of de- 

 noting in single phrases both the num- 

 ber of leaflets and the kind of com- 

 pounding. 



157. Of foliage-leaves having certain peculiarities in structure, the 

 following may be noted : 



Fig. 160. A twice-pinnate (abruptly) leaf oi the Honey-Locust 

 Fig. 161. Ternately decompound leaf of Mwddow Rue. 



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