ON THE FORMS OF STIPULES 



169 



modifications to crowding, the obstruction of light, or 

 exposure to the same, and to the form or position of the 

 buds they have to protect. 



Sometimes the gradation is regular. Thus, in 

 Nuttallia cerasifoi-mis the winter-bud is covered with 

 numerous scales, which are leaves wholly reduced to 



Fig. 292. Leaves of Nuttallia cerasifokmis. 



a, with entire sheath ; 6, showing indications of stipules ; c, with stipules in 



ultimate form. 



their sheaths. The outer ones are very short, rounded, 

 ovate, or triangular, not lengthening when growth 

 commences; the inner ones lengthen, becoming linear, 

 cuspidate, concave, rolled round the bud, pale green, 

 almost colourless, membranous, and ciliate at the 

 margin. 



The first leaf in the bud having a lamina is spathu- 



