102 MORPHOLOGY OF LEAVES. 



Lupines. More commonly there are only five to nine, or only 

 three, rarely two, or even a single one. 



197. Number of leaflets may be indicated by an adjective 

 expression composed of the proper Latin numeral prefixed to 

 foliolate (Foliolum, diminutive of folium, answering to leaflet) . 

 Thus, bifoliolate, of two leaflets; trifoliolate, of three leaflets; 

 quadrifoliolate, of four ; quinquefoliolate, of five : plurifoliolate, or 

 multifoliolate, of several or numerous leaflets, &c. These terms 

 are still more descriptive when accompanied by the word pin- 

 nately or palmately, indicative of the kind of compound leaf; as, 

 palmately or digitately trifoliolate (common Clover-leaf, Fig. 211), 

 or 5-foliolate, as in Buckeye (Fig. 206), and so on. Also, pinnately 

 IG-foliolate, as in Fig. 205, or 17-foliolate, as in Fig. 203 ; 

 pinnately trifoliolate, as in Phaseolus, and in the low Hop-Clover, 

 Trifolium procumbens. 1 



198. But, in either class of compound leaves, the leaflets may 

 be reduced to a minimum number. A pinnately trifoliolate leaf 

 is one of the impari-pinnate kind reduced to three leaflets, to one 

 pair and the odd one ; and this is distinguished from a palmately 

 trifoliolate leaf by the attachment of the pair at some distance 

 below the apex of the petiole, and by the articulation above this, 

 which marks the junction of the terminal leaflet's petiole (or its 

 base, if sessile) with the rhachis or common petiole. 



199. Unifoliolate compound leaves (by no means a direct con- 



tradiction in terms) are by this articulation distin- 

 guished from simple leaves which they simulate. 

 See the leaf of the common Barberry, Fig. 207. 

 In other species, of the Mahonia section, the leaves 

 are all pinnately 3-9 -foliolate, with well-developed 

 common petiole : in the true Berberis, they are all 

 thus reduced to the terminal and long-petiolulate 

 leaflet, on an almost obsolete petiole. Orange and 

 Lemon leaves are in similar case, but with the joint 

 close to the blade. A comparison with near rela- 

 tives shows that these are also unifoliolate leaves 



of the pinnate kind ; though this could not be ascertained by 



inspection. 



200. Decompound or Twice and Thrice Compound Leaves. These 

 are to once pinnate or once palmate leaves what the latter are to 



1 In pinnate leaves, each leaflet usually has its opposite fellow, and the 

 number may be \ndicated by the pairs, as unijugate, bijugate, trijugate, and 

 pluri jugate, according to the number ofjuga, or pairs. 



FIG. 207. Unifoliolate leaf of Berberis vulgaris, with partial petiole articulated to 

 the extremely aha t true petiole. 



