68 



ZSSSOlfS WITS PLANTS 



three-eighths arrangement? Let the pupil examine 

 osage orange, live-for-ever, holly, plantain, and find 

 out. He may also examine the 

 scales on the house-leek (or old-hen- 

 and-chickens of the gardens), bud- 

 scales, pine cones, scaly bulbs, leaves 

 of palms, and of firs and pines, the 

 seeds in a sunflower head, for other 

 and more involved cycles. This 

 arrangement of the parts is known 

 as phyllotaxy, literally " leaf-arrange- 

 ment," but it is generally more easily 

 studied upon winter twigs than upon 

 foliaceous shoots. 



71. The ailanthus (or "tree of 

 heaven") has a two-fifths phyllotaxy, 

 like the apple, cherry, peach, plum, 

 willow, and many other common 

 trees (for this is the most frequent 

 arrangement). Yet Fig. 67 is the 

 tip of a branch of this tree. 

 The pupil wUl see that the buds 

 have no order. The branch is much 

 flattened or fasciated. This fascia- 

 tion or abnormal flattening is not 

 rare, but is commonest in plants 

 of comparatively soft tissue, and is usually asso- 

 ciated with very vigorous growth. The point 



Fio. 67. 



Fasciated branch of 

 ailanthus. 



