82 



A TEXTBOOK OF BOTANV 



ICh. III. 10 



;i kind nf liranching 

 of tho face of the 

 leaf. Such seems the 

 case in the Ud of the 

 Nepenthes pitcher 

 earher mentioned, 

 and in the corona, 

 or crown, of t.he 

 petals of some 

 flowers, notably the 

 Daffodil (Fig. 230). 

 Thus we see that 

 the leaf, though 

 having a definite 

 and t3qiical primary 

 function and struc- 

 ture, is yet liiglil.v 

 plastic in all of its 

 features, and can he 

 led along many dif- 

 ferent lines of de- 

 velopment. Such 



Fig. 57. — Special forms of .stipules: X 5. morphological plas- 

 Euphorbia, paired spines: Galium, with t\^'o ticitv is character- 

 opposite leaves simulating a 6-leavGd whorl :.."„., 

 Tulip Tree, bud scales : Polygonum, united in a IStlC 01 ail parts 01 

 .sheath (ochrea) around the stem : Violet, acces- living bcino'S and is 

 sory foliage. ^ . .* 'i. 



one of their distinc- 

 tive proi)erties (page 39). The tracing of such lines of 

 development is the distinctive provinc(^ of morjihology. 



10. The Nutrition of Plants Which Lack 

 Chlouophtll 



While most infants poss(>ss chlorophyll and m:ike their 

 own food, there are some whicli d(i not. If, now, all plant 

 food is based on grape sugar made in green tissues, how 

 do these chlorophyll-less kinds .secure their supply? The 



