86 



ELEMENTS OP BOTANY. 



this ? Are the spaces between the edges of the leaves large or small 



compared with the leaves themselves ? 



Pull off a single leaf and make a very careful sketch of its under 



surface, about natural size. Label the broad expanded part the blade, 



and the stalk by which it is attached to the twig, leaf-stalk or petiole. 

 Study the outline of the leaf and answer these questions : 

 (a) What is the shape of the leaf, taken as a whole ? (See Fig. 63.) 



Is the leaf bilaterally symmetrical, i.e., Is there a middle line running 



I. n. in. IV. 



V. VI. VII. VIII. 



FiO. 64. — Shapes of Tip of Leaf. 

 I, mucronate, tli© midrib prolonged into a 

 hardsliort point'; II, cuspidate, tapering 

 into a stiif point ; III, acute ; IV, rounded ; ^ 

 V, acuminate or taper-pointed ; VI, retuse, 

 witli tlie rounded end sliglitly notclied ; 

 VII, emarginate, deeply notclied; VIII, 

 truncate, with the end cut off rather 

 squarely. 



Fig. 65. — Shapes of Bases of 

 Leaves. 

 1 , heart-shaped (unsymmetrically> ; 

 2, arrowHBhaped ; 3, halberd- 

 shaped. 



through it lengthwise, along which it could be so folded that the two 

 sides would precisely coincide ? 



(6) WTiat is the shape of the tip of the leaf ? (See Fig. 64.) 



(c) Shape of tlie base of the leaf. (See Fig. 65.) 



(d) Outline of the margin of the leaf ? (See Fig. 66.) 



cherry, apple. Most of the statements and directions above given would apply to 

 any of the leaves just enumerated. If this chapter is reached too early in the season 

 to admit of suitable material being procured for the study of leaf arrangement, that 

 topic may be omitted until the leaves of forest trees have sufficiently matured. 

 1 Any form intermediate between III and IV would he called obtuse. 



