ON THE FORMS OF STIPULES 173 



protected by the petioles of one or more of the last- 

 developed leaves, which are either small or imperfect. 



But few attempts have yet been made to explain 

 the differences in the forms of stipules. Some have been 

 indicated in the preceding pages, and it may be interest- 

 ing to refer to a few cases in more detail. For instance, 

 among the Clovers (Trifolium), the common Red Clover 

 (Trifolium pratense) has the strongly veined connate 



FIG. 294. TRIFOLIUM PRATENSE. 

 Flower-hud with the pair of protecting leaves. Nat. size. 



stipules (fig. 294) ovate, the free part short, triangular, 

 and 'ending in a setaceous, applied point. The upper 

 ones are somewhat dilated. In White Clover (T. 

 repens) (fig. 295) they are all comparatively narrow, and 

 subulate at the free end. 



This difference may perhaps be accounted for by the 

 different arrangement of the flower-bud. In T. pratense 

 the head is sessile (fig. 294) and the bud is protected 

 by the broad stipules. Hence, also, perhaps the upper 



