220 BRITISH FLOWERING PLANTS chap. 



the pollen, while flies come principally to lick the layer 

 of honey. From the position of the flowers pollen must 

 often fall from one flower on to the stigma of another. 



I was long puzzled as to the reason for the great 

 diff'erence in the form of the leaves of our two species 

 of Viburnum, but it may perhaps be explained by the 

 following suggestions, which I brought forward in a 

 paper read before the Linnean Society in 1890,^ and 

 in my book On Buds and Stipules. V. Lantmia has 



Fig. 146. — Viburnum Opulus. Shoot, with flower and fruit. 



leathery leaves, tomentose on the nerves, which, more- 

 over, are when young protected by a thick felt of stellate 

 hairs. V. Opulus, on the contrary, has more delicate 

 leaves, glabrous above, pubescent beneath. They are 

 protected in the bud by the lower leaves, which are 

 leathery, and serve merely for this purpose. For facility 

 of packing in the confined space of the bud they are 

 folded up, and hence the lobed form. They also present 

 curious stipules or stipuliform appendages, which fill up 

 and thus utilise a space at the base of the bud which 

 would otherwise be empty. ^ The leaf -stalks bear 

 one or more cups which secrete nectar. This is also 



' Journal Linnerm Soc. (Bot.) xxviii. 

 ^ This is described more fully in my Buds and Stipules, p. 40. 



