306 NATUKE OF STIPULES. [BOOK i. 



Polygonum (fig. 61. a), they have been termed ochrea by 

 Willdenow. In pinnated leaves there is often a pair of 



fig. 61. 



stipules at the base of each leaflet, as well as two at the 

 base of the common petiole : stipules, under such circum- 

 stances, are called stipels. 



What stipules really are has been a matter of doubt. De 

 Candolle seems, from some expressions in his Organographie, 

 to have suspected their analogy with leaves ; while, in other 

 places in the same work, it may be collected that he rather 

 considered them special organs. I have always been of 

 opinion that, notwithstanding the difference in their appear- 

 ance, they are really accessory leaves : first, because they are 

 occasionally transformed, in Rosa bracteata, into pinnated 

 leaves; secondly, because they are often undistinguishable 

 from leaves, of which they obviously perform all the functions, 

 as in Lathyrus, Lotus, and many other Leguminous plants : 

 and, finally, because there are cases in which buds develope 

 in their axils, as in Salix, a property peculiar to leaves and 

 their modifications. This view has been confirmed by the 

 researches of De Mercklin as given in previous pages. 



Among Cucurbits exist, in the place of stipules, processes 

 having the appearance of tendrils, which De Candolle, after 

 Seringe, supposed them to be. The Bravais' have suggested 

 that these tendrils are rather to be regarded as accessory 

 buds, (Annales des Sciences, 2 s. viii. 20.) But according to 

 Payer, they are the lateral ribs of the true leaf, upon which 



