98 



TJJE LEAF 



■n-ith the petiole distinguishes this last case from a simple leaf. Id 

 other species of these yeiiera the lateral leallels also are present. 



184. The leaflets of a compound leaf may L>e either enlire (as iu 

 Figs. 12i-126), or serrate, or lobed, cleft, parted, etc. ; in fact, may pre- 

 sent all the variations of simple leaves, 

 and the same terms equally apply to 

 them. 



185. When the division is carried 

 so far as to separate what would be 

 one leaflet into two, three, or several, 

 the leaf becomes douhbj or twice com- 

 pound, either pinnatehj or palmaleli/, as 

 the case may be. For example, while 

 the clustered leaves of the Honey 

 Locust are shnpbj pinnale, that is, once 

 pinnate, those on new shoots are bi/iiii- 

 nute, or twice pinnule, as in Fig. 128. 

 When these leaflets are again divided 

 in the same way, the leaf becomes 

 'Jirice pinnate, or tripinnate, as in many 

 Acacias. The first divisions are called 

 pinnce; the others, pinnules; and the 

 last, or little blades themselves, 

 leaflets. 



186. So the palmate leaf, if again compomided in the same way, 

 becomes twice palmate, or, as we hwy when the divisions are iu threes, 



twice tcrnale (in Latin form Ijilcrnale); if a 

 third tiuK.' compounded, llirice tcrnnlc or Irilcr- 

 nale. But if the division goes still further, 

 or if the degree is variable, we simply say 

 that the leaf is dccompounil ; either palmately 

 or pinnatelj' decompound, as the case may be. 

 Thus, Fig. 129 represents a four times ter- 

 natelj^ conqionnd (in other "words a ternateh/ 

 decompound^ leaf of a common JMeadow Hue. 

 187. AVIien the botanist, in describing 

 12;i. Ternaiely decom- loaves, wishes to express the number of tlifi 

 pouutl leaf "^'f T i3 i 1 i Ti ii 



\r I T3 leaflets, he may use terms hke these: — 



Meadow Rue. .' , ■ 



Unifoliolale, for a compound leaf of a single 

 leaflet; from the Latin unum. one, and foliolum. leaflet. 



Bifoliolate, of two leaflets, from the Latin bis, t\vice, and foliolum, 

 leaflet. 



Trifoliolale for lernnte), of three leaflets, as the Clover, and so on, 

 Palmately hifolinlate, Irifoliolate, quadrifoliulate, plurifoliolate (of 

 several leaflets), etc. : or else 



12S. A twice-piunate (abruptly) 

 leaf of the Honey Locust, 



