170 



ORGANOGRAPHY. 



Fig. 340. as in some species of Acacia. 



The leaflets borne by the partial 

 or secondary petioles are com- 

 monly termed pinnules. When 

 the pinnules of a bipinnate leaf 

 become themselves pinnate, it is 

 tripinnate {fig. 339), as in the 

 Meadow Kue ( Thalictrum minu.<i). 

 When the division extends be- 

 yond this, the leaf is decompound 

 {fig. 340), as in many Umbel- 

 liferous Plants. 



2. Pahnately- veined Compound 

 leaves. — Such a leaf is produced 

 when the ribs of a palmately 

 veined leaf bear separate leaflets. 

 These leaves are readily distin- 

 guished from those of the pinnate 

 kind, by their leaflets coming oft 

 from the same point. We distin- 

 guish several kinds: thus, a leaf 

 is said to be binate, bifoliate, or 

 unijugate, if it consists of only 

 two leaflets springing from a com- 

 mon point {fig. 341), as in Zygophyllum ; it is ternale or tri- 

 foliate if it consists of thi-ce arranged in a similar manner {figs. 

 327 and 342), as in the genus Trifolium (Trefoil), which 

 receives its name from this circumstance ; it is quadrinate or 

 quadrifoliate if there are four leaflets {-fig. 343), as in Herb 



Fig. 340. A decompound leaf. 



Fig. 341. 



Fig. 342. 



Fig. 343. 



Fig.M^. A binnte leaf. Fig. S42. Ternate or trifoliate leaf. 



Fig. .■M.J. Quadrifoliate leaf of Jfarsiku >/iuulri/olia. 



Paris {Paris (juadrifolia) ; it is qninate or qninqncfoliate'if there 

 are five {fig. 344), as in Polenlilla argentea and alba ; it is sep- 

 tenate or srptetnfoliate, if there arc seven {fig. 34.0), as in tlic. 

 Ilorsc-chestnui and some Potentillas ; it is multlfoliatc if there 



