vi.] WATER PLANTS OFTEN GLABROUS. 127 



even an ant could not force its way in : twenty are 

 aquatic, and hence more or less protected from the 

 visits of ants and other creeping insects; thus we 

 shall frequently find that if, in a generally hairy 

 genus, one or more species are aquatic, they are also 

 glabrous as, for instance, Viola palustris, Veronica 

 anagailis, V. beccabunga, and Ranunculus aquatilis. 

 Polygonum amphibium is peculiarly interesting, 

 because, as Kerner has pointed out, aquatic speci- 

 mens are glabrous ; while in those living on land the 

 base of the leaf produces hairs. Half a dozen are 

 early spring plants which flower before the ants are 

 roused from their winter sleep ; about the same 

 number are minute ground plants to which hairs 

 could be no protection ; three or four are night 

 flowers ; there still remain a few to be accounted for, 

 which would have to be considered individually, but 

 probably the evidence is sufficiently complete to 

 justify the general inference. 



Lastly, I must not omit to mention the hairs which 

 have a glandular character. 



The next point to which I would call attention is 

 the remarkable manner in which certain forms repeat 

 themselves. In some cases, there seems much reason 

 to suppose that one plant derives a substantial ad- 

 vantage from resembling another. For instance, 

 Chrysanthemum inodorum, the scentless Mayweed, 

 very closely resembles the Chamomile in leaves, 

 flowers, and general habit. The latter species, how- 

 ever, has a strong, bitter taste, which probably serves 

 as a protection to it, and of which also, perhaps, the 

 scentless Mayweed may share the advantage. These 



