FORMS OF LEAVES 



413 



s^ ^t 



Then we may have simple or compotmd leaves, all in 

 one piece in the first instance, or divided up into two or 

 ftiore pieces springing from a single stalk, when they are 

 termed compound leaves ; an enormous nvunber of patterns 

 represent these two divisions. With respect to other out- 

 lines, the leaf may be entire, that is with unbroken margin ; 

 but when this margin is saw-toothed, it is said to be serrate 

 (Figure 90). When the teeth point outwards, it is dentate 

 (Figure 91) ; if the margin be scalloped it is said to be cre- 

 nate (Figure 92), and if wavy it is undulate (Figure 93). If 

 markedly wavy it is sinuate (Figure 94) . Finally, the mar- 

 gin may be incised or jagged (Figure 95). 



Sometimes leaves are more deeply cut than this, when 

 they are said to be lobed the projections being called lobes 

 and they may thus be 2-lobed, 3-lobed, many-lobed, etc 

 Simple lobed leaves are shown in Figures 63 and 79; 

 when sharply lobed it is cleft (Figures 64 and 77), and 

 such leaves may be bifid, trifid, quadrifid, etc., even 

 mullifid, giving rise to segments to correspond. If not 

 cleft, the leaf may be parted by deeper incisions extend- 

 ing almost to the midrib (Figures 65 and 78); so we 

 have them 2-parted, 3-parted, mvdtiparted, etc. Should 

 the incisions reach the midrib, the leaf is said to be 

 divided, that is bisected, trisected, and so on (Figures 81 

 and 83). Figure 97 shows a palmate leaf, or five leaflets 

 (Sweet Buckeye). 



To describe the degree as well as the mode of division, 

 other terms are employed, as feather-veined, that is pin- 

 nately-veined and radiate-veined or palmately-veined leaves. 

 Figures 63, 64, 65 and 83 are examples of the first, and 

 77, 78, 79 and 81 examples of the second. Such terms as 

 palmately lobed (Figure 79), palmately cleft (Figure 77), 



palmately parted (Figure 78), and palmately divided (Fig- 

 ure 81) are self-evident. 



Compound leaves exhibit leaflets as in Figure 96 which 

 are said to be pinnate; there are also palmate compound 

 leaves, sometimes called digitate (Figure 97). Compound 

 leaves like in Figure 96 may have one or two leaves at 

 the distal end of the stem, or terminate in a tendril as in 

 the common garden pea. A variety of other terms are 

 employed to describe the compounding of leaves; for 

 example, the foliage of the Meadow Rue is said to be ter- 

 nately-decompounded. But space will not admit of giving 

 more of them here. 



Perfoliate leaves is where the stem seems to run through 

 or perforate the leaf near its base (Fig. 84, Bellwort) ; this 

 is definitely so in the lower leaves, and less so as we ascend 

 toward the end of the stem, where the last leaf is sessile. 

 Sometimes the perfoliation is due to two leaves amalgamat- 

 ing (connate-perfoliate), as in true honeysuckle vines (Fig- 

 ure 82), and here the perforations disappear as the main 

 stem is approached. 



A SIGNIFICANT indication of the interest taken in 

 forestry in California is the popularity of a course in 

 Elementary Forestry at the University of California. This 

 course is designed, not for the professional forestry 

 student, but to supply information on forestry matters 

 and methods for its general educational value. Seven 

 colleges of the University are represented in the enrol- 

 ment Letters and Science, Agriculture, Commerce, 

 Chemistry, Civil Engineering, Mechanical Engineering, 

 Mining. Statistics recently compiled show that during 

 the past year 382 different students have been under 

 instruction by the Forestry Division, including both those 

 in professional and in non-professional courses. 



