109 



the amount of its hairiness^ as to be almost glabrous; and 

 species usually glabrous, or nearly so, from being almost free 

 from down, frequently become densely clothed with hair. A 

 very curious instance of this occurs in the Silene injlata, Sm., 

 a plant in its normal state found entirely free from hairs ; but 

 of which, in the variety b. hirsuta, the leaves and stem arc 

 densely clothed with hairs, as high as its peduncle, which is 

 perfectly smooth ; and in another variety mentioned by 

 Hooker, it is covered throughout with down, even extending 

 over the calyx. Several other species of this genus vary con- 

 siderably in the nature and extent to which these hairs are 

 found ; indeed I may say the whole of the natural order 

 Caryophylleee is disposed to sport in this manner. It there- 

 fore becomes necessary in such cases to resort to other and 

 more permanent characters, and if possible to ascertain some 

 less liable to variation, such as the shape of the leaves, position 

 of the flowers, etc. But here again we are frequently met by 

 anomalies, which compel us to have recourse to habit to dis- 

 tinguish our plant. 



In some cases we find the forms assumed by the leaves very 

 constatit, whereas in others the same parts are equally varied, 

 as for instance in the group of aquatic Ranuncnli ; the type 

 of this section being Ranunculus aquatilisy Linn., the reniform 

 leaves of which are gradually more and more divided, until we 

 arrive at the mere capillary segments found in the leaf of 

 R. fluitans. It is quite evident then in this case, that we 

 must not expect to find rehable characters in the leaf for our 

 specific distinctions. This species or group is divided bv 

 many botanists into three, viz., the R. aqualiluj circinatus, 

 and fluitans ; but the question is, are these three species 

 really distinct? I apprehend not, for we find intermediate 

 states which appear to possess characters appertiiining to ail 

 three species, and from the variety of circumstances under 

 which they grow, I think there is sufficient to account for tiie 

 apparent differences. 



