ON THE NATURE OF STIPULES 



199 



correspond to the auricles of other Crucifers which are 

 continuous with the margin of the leaf. 



The Umbellifers (Carrot, Parsnip, Parsley, &c), 

 again, have the petioles flattened and broad, often 

 forming a sheath. In some the upper or smaller 

 part of the sheath becomes detached. When this has 



Fig. 314. Leaf of Parsley. 



Fig. 315. Leaf of Ostruthium. 



proceeded sufficiently far the free lobes may fairly be 

 called stipules. Indeed, it is obvious that there may 

 be every intermediate gradation between a species 

 with a merely flattened petiole and one with true 

 stipules. Nay, such transitions may and do occur in 

 the same plant, and even in the same bud. 



