66 



MORPHOLOGY OF LEAVES AS FOLIAGE. [lESSON 9. 



Some Lupines have nine or eleven ; the Horsechestnut has seven, 

 the Sweet Buckeye more commonly five, the Clover three. A pin- 

 nate leaf often has only seven or five leaflets, as in the Wild Bean 

 or Groundnut ; and in the Common Bean it has only three ; in 



some rarer cases only two ; in 

 the Orange and Lemon only 

 one ! The joint at the place 

 where the leaflet is united with 

 the petiole alone distinguishes 

 this last case from a simple 

 leaf;* 



' 170. The leaflets of a com- 

 pound leaf may be either entire 

 (as in Fig. 126-128), or ser- 

 rate, or lobed, cleft, parted, 

 &c. : in fact, they may pre- 

 sent all the variations of simple 

 leaves, and the same terms 

 equally apply to them. 



'171. When this division is 

 carried so far as to separate 

 ^ what would be one leaflet into 

 two, three, or several, the leaf 

 becomes doubly or twice' com- 

 pound, either pinnately or pal- 

 ™ mately, as the case may be. 



For example, while some of the leaves of the Honey .-Ldcust are 

 simply pinnate, that is, once pinnate, as in Fig. 128, the greater part 



* When the botanist, in describing loaves, "wishes to express the ' number of 

 leaflets, he may use terms like tliese : — ' 



Unifoliolate, for a compound leaf of a single leaflet ; from the Latin unum, one, 

 anifoliotum, leaflet. 



Bifoliolate, of two leaflets, from the Latin bis, twice, a-ndfqliolum, leaflet. 



Trifoliolate (or temate), gf three leaflets, as the Clover; and so on. 



When he wonld express in one phrase both the number of leaflets and the way 

 the leaf is compound, he writes : — 



Palmatdy bifoliolate, trifoliolate, plurifiliolate (of several leaflets), &c., or else 



Pinnatdy bi-; Iri-, quadri-, or pluri-foliolate (that is, of two, three, four, five, or 

 several leaflets), as the case may be. 



FIG. 180. A twice-pinnato (alituptly) loaf of the Honev-Locust. 



