22 BOTANY. 



Is it membranous ? waxy ? gummy ? lined with down, wool, 

 or dense hairs ? or is it varnished on the outside ? Why 

 should these parts of winter buds be called protective cover- 

 ings ? Are summer-formed buds naked or protected ? Can 

 you find the young leaves within these outer bud-scales ? 

 The way in which these tiny leaves are folded, rolled, and 

 arranged in the bud is called vernation. To study verna- 

 tion, look for buds that are just opening, where the young 

 leaves still keep the shape they had when packed in the 

 bud. If you have a magnifying-glass, you will find it use- 

 ful now. The modes of folding and rolling are named 

 as follows : When a leaf is folded so that the apex comes 

 near the base, as shown in the diagram (Fig. 68), it is said 

 to be reclinate, or inflexed ; when it is folded at the mid- 

 rib, and the margins of the right and left half come to- 

 gether (Fig. 69), the leaf is conduplicate ; when the leaf is 

 plaited like a fan (Fig. 70), it \* plicate. Or a leaf may be 

 rolled from apex to base (Fig. 71), when it is said to be 

 circinate ; or, from one margin to the other, in a single 



FIG. 68. FIG. 69. FIG. 70. FIG. 71. FIG. 72. 



coil, convolute, as Fig. 72 ; or, the two margins may both 

 be rolled inward on the upper surface of the leaf, toward 

 the midrib, involute (Fig. 74). When they are rolled simi- 

 larly on the under surface (Fig. 73), the form is revoluie. 

 Leaves are always arranged in the bud either in a val- 

 vate or imbricate manner. The best way to study their 

 arrangement is to cut off the top of the bud with a sharp 

 knife and look down on the cut edges, which will show, 

 not only whether the leaves are imbricate or valvate, but 

 other peculiarities they may exhibit. 



