ON STIPULES 45 



and V. Opulus the hairiness of the former and the 

 smoothness of the latter ; on the lobed form of the 

 leaf in the latter ; and, lastly, oh the presence of the 

 honey-glands and the peculiar stipuliform appendages 

 in V. Opulus, neither of which occur in V. Lantana. 



In support of the above suggestions I may refer 

 to the interesting analogy afforded in a totally 

 different family by the genus Spircea. Here we find 

 some species with entire, some with pinnate leaves ; 

 while those of 8. opulifolia, as the name denotes, closely 

 resemble those of Viburnum Opulus. Now the entire- 

 leaved species of Sprircea, like those of Viburnum, have 

 no stipules ; while Spiraea opulifolia agrees with Vibur- 

 num Opulus not only in the shape of the leaves, but in 

 the mode of folding in the bud. and also in the presence 

 of subulate, acuminate, stipuliform appendages. 



I might give other cases, but the above will, I 

 think, be sufficient. It seems clear that the answer 

 which we had provisionally arrived at from a study of the 

 Hock Roses is fully borne out by the examination of other 

 families, and that when the bud needs protection and 

 the petiole is narrowed, this function is performed by 

 the stipules ; while, when there are no stipules, the 

 bud is protected in some other way, and generally by 

 the widened base of the leaf-stalk. 



But though the protection of the bud is the general, 

 it is, as we shall presently see, by no means the only 

 function which stipules perform in the economy of plants. 



