THE COMPOUND LEAF 189 



etc.) or Palmatifid C Figs. 540 and 546), according to the character of its 

 venation. In all forms of lobed, cleft, parted or divided leaves, it is 

 necessary that the detailed characters of the lobes and of the sinuses 

 should be specified. The lobe may be acute, while the sinus is rounded 

 (Fig. 543), or the reverse may be true (Fig. 545), or both may be acute 

 or both obtuse (Fig. 548). The sinuses as well as the lobes frequently 

 possess definite and characteristic outlines, indicated by terms such 

 as have already been defined in connection with the leaf. When the 

 teeth and sinuses are outlined by straight lines and sharp terminations, 

 as though notched out by a pair of scissors, the margin is said to be 

 Incised (Figs. 540 and 546). When the divisions and sinuses are long 

 and narrow in addition to being incised, it is called Laciniate (Fig. 540). 

 When the margin of a leaf is turned downward or backward or rolled 

 backward, it is said to be Revolute. Ordinarily the revolution is very 

 slight (Fig. 541), but occasionally, particularly upon drying, it will be 

 found extreme, each half of the leaf forming a roll, the two meeting 

 back of the midrib (Fig. 542). 



Before proceeding to speak of the forms of compound leaves, it 

 should be stated that when one of the terms above defined (and the 

 same is generally true of descriptive terms used in other parts of the 

 work) terminates in the ending ate or oid, it sometimes indicates that 

 the condition tends toward but does not quite reach that named by 

 the term to which the ending is appended. For example, triangulate 

 means inclining toward triangular. The student will also note that 

 between nearly all the forms of leaves and the characters indicated by 

 the terms above defined, there are intermediate forms connecting them 

 with others. 



Inasmuch as it is necessary in description for such forms to be 

 indicated, the method is resorted to of employing the two terms con- 

 nected by a hyphen. Thus, Lance-ovate, or Ovate-lanceolate (Fig. 

 497) indicates that the form is intermediate between lanceolate and 

 ovate; crenate-dentate and serrate-dentate are similar illustrations. 



A similar intermediate condition is sometimes indicated by prefixing 

 the term sub, thus sub-cordate, sub-sessile, sub-acute. Other inter- 

 mediate terms very commonly employed are acutish and obtusish. 



The Compound Leaf. — In the lobed leaves which we have already 

 examined, even the most deeply divided of them, the lobes are seen to 

 be connected with one another at the base by portions of the common 

 blade, so that a complete division of the blade into separate parts has 

 not taken place. In the leaves which we are now to examine, such 



