Wibcn tbe 'MooCjs are Xeat*green 61 



typical, or chief form of the leaf, and when there is a 

 departure from it we call such departure a " modified 

 leaf." 



The white thick scales of the onion or lily bulb 

 are leaves ; the scales which wrap up buds, the coty- 

 ledons, the thick divisions oT the house-leek, the 

 tendrils of the pea-vine, the thorns of the barberry, 

 the brown woody scales of the pine, or larch-cone, the 

 needles of the pine, the little, odd-shaped bracts on 

 stems, are all leaves. In fact, all the parts of the 

 flower, the calyx, petals, stamens, and pistils, are 

 really leaves. When we now speak of leaves, we 

 mean leaves in the popular sense, the common leaf, 

 which is the type or pattern of leaves usually borne 

 on a stem, a green, expanded body, performing for 

 the whole plant various and necessary offices. 



Early in April we find the leaf buds unfolding 

 upon the sides of the stems, or pushing up through 

 the ground. Some of these buds are placed opposite 

 to each other upon the stem, some are in rings 

 around the stem, others are set alternately, others 

 spirally, so that if you follow with a thread the 

 placing of a certain number of buds you will see 

 that the thread has made a complete circuit of the 

 stem, and then another. AVhere the leaves are in a 

 spiral placement it is merely a whorl drawn out ; 

 Avhere there is a whorl it is but a compressed spiral. 



