ON STIPULES 



29 



When stipules survive the rest of the leaf to which 

 they belong, this generally has reference to the protec- 

 tion of the buds. Thus, in Magnolia Umbrella the 

 leaf terminating each year's growth is small, and 

 eventually the blade becomes disarticulated just above 

 the stipules, which are adnate to the leaf-base and 

 enclose the bud (fig. 38). These stipules are in this 

 species the only ones which survive the leaf-blade. 



si-.. 



-Sc 



FIG. 35. FIG. 36. 



PETTERIA RAMENTACEA. 



1'iG. 35. Portion of shoot in winter, x 2. 



FIG. 36. Ditto in spring, x2. Sc, scar 



of fallen leaf; St, stipules completely 



covering the bud in fig. 35, in fig. 36 



pushed aside by the developing bud (&). 



FIG. 37. POPULUS NIGRA. 

 TERMINAL WINTER-BUD, 

 showing a pair of per- 

 sistent stipules (st) be- 

 longing to a leaf of last 

 season, x 2. 



Some other species of Magnolia for instance, a 

 garden hybrid, M. Soulangiana agree with M. Umbrella 

 in these respects. 



In some cases, however, as in the so-called Acacia 

 (Robinia), the thorny stipules assist in the protection of 

 the plant as a whole. 



