60 BOTANY FOR BEGINNERS. j Ch. X, 



238. The " fall of the leaf" may be referred to two causes-, 

 the death of the leaf, and the vital action of the parts to which 

 it is attached. If a whole tree is killed by lightning, or anv 

 sudden cause, the leaves will adhere to the dead branches, be- 

 cause the latter have not the energy to cast them off. 



239. The richness and variety of colouring exhibited about 

 the end of autumn, by American groves and forests, is splendid 

 beyond the power of the painter to imitate. Yellow, red, and 

 brown, are the most common colours of the dying leaf; but 

 these colours vary from the brightest scarlet, and the deepest 

 crimson, to different shades of yellow, from the deep orange to 

 Jie pale straw colour. 



Appendages to Plants. 



240. Plants have a set of organs called by the general name 

 of appendages. These we shall now describe. 



Fig. 38. 



241. Stipiiles are 

 membranous or leafy 

 scales, usually in 

 pairs, at, or near the 

 base of the leaf or 

 petiole. They are 

 various in their forms 

 and situations, are 

 found in most plants, 

 but are sometimes 

 wanting. In the garden violet, Viola tricolor, (Fig. 3S, a, a,) 

 the stipules are of that form called lyrate pinnatifid, while the 

 true leaf (6) is oblong and crenate. The most natural situation 

 of the stipules is in pairs, one on each side of the base of the 

 footstalk, as in the sweet pea ; some stipules fall off almost as 

 soon as the leaves are expanded, but in general, they remain as 

 long as the leaves. 



242. Prickles, arise from the bark; they are sometimes 

 straight, sometimes hooked, and sometimes forked. They are 

 usually found upon the stem, as in the Rose ; but in some cases, 

 they cover the petiole, as in the Raspberry ; in others, they are 



238. To what may the fall of the leaf be referred 7 



239. What is said of the appearance of American forests in the Au 



240. What organs have plants besides those already named 1 



241. Describe stipules. 



242. Describe prickles. 



