ON THE FORMS OF STIPULES 167 



sented by a small black point (fig. 287). One or two suc- 

 ceeding ones bear a small lamina sessile on the sheath, 

 which is wholly adnate to the thin, dilated base of the 

 petiole, and membranous, especially outside of the three 

 vascular bundles (fig. 289). One or two of the leaves 

 succeeding this have a well-developed lamina, and the 

 sheaths partly separated from the petiole and corre- 

 sponding to stipules (fig. 290). The stipular sheaths on 

 succeeding leaves are shorter and wholly adnate to the 

 petiole, strongly fringed on the margin, with the hairs 

 on the upper portion longest and more or less branching 

 (fig. 291). 



This series is shown in figs. 287291. 



POTENTILLA 



Most of the species of Potentilla are herbaceous 

 perennials, some with evergreen, others with deciduous 

 leaves. The different forms of stipules found on the 

 same plant appear to have reference to its habit. 

 Usually a large number of the leaves are radical, spring- 

 ing from the crowns or growing- points of the rootstock, 

 which is often buried to a greater or less extent in the 

 soil. The long stipules, adnate to the petioles, and 

 more or less completely overlapping the younger mem- 

 bers, form a very effective protection to the buds, either 

 while resting, or while pushing up their young leaves 

 and flowering stems from beneath the soil. The stipules 

 of these leaves sometimes remain beneath the soil, some- 



