Habits and Habitats of Plants. 151 



witness to by the names of plants ; not only in scientific termi- 

 nology, — e.ff., the numerous specific names ending in ides («^o«, 

 form), — but also by the popular names. Thus we have ash and 

 mountain-ash ; chestnut and horse-chestnut ; nettle and dead- 

 nettle; flax [Linum) and toad-flax (Lrnana) ; black bryony and 

 white bryony ; alder and berry-bearing alder ; purple loosestrife 

 and yellow loosestrife: all of these belonging respectively to 

 widely different orders. 



Sometimes, however, the similarity thus noted in popular names 

 may lie in properties or uses rather than in appearance {e. g., 

 sorrel and wood-sorrel; lettuce and lamb's-lettuce), and in other 

 cases it is difficult to trace the resemblances which have given 

 rise to a similarity of name : as agrimony and hemp-agrimony ; 

 violet and water-violet {Hottonia). 



The chief reason of these resemblances of form seems to be 

 that plants of different orders have, in the struggle for existence, 

 betaken themselves to similar habitats — the " habitat " of a plant 

 being the sort of place where it grows — and have adapted them- 

 selves to those habitats by acquiring forms and habits suited 

 to their station in life ; and therefore, necessarily, in many cases 

 these adaptations of unallied plants have tended in similar 

 directions. 



Another explanation, however, may in some instances hold 

 good. It is well known that in the animal kingdom certain 

 species, — e.g., of insects, — escape from their enemies by their 

 resemblance to other species which are armed, uneatable, or in 

 other respects objectionable ; and it is conceivable that among 

 plants a similar mimicry may sometimes have been brought 

 about through natural selection, by a plant deriving benefit from 

 its resemblance to another plant which possessed some property 

 rendering it objectionable to herbivora and insects. Thus Sir 

 John Lubbock suggests that the dead-nettle may be protected by 

 its resemblance to the stinging-nettle, and the scentless May-weed 

 {Matricaria inodora) by its resemblance to the strong-flavoured 

 chamomiles. The dead-nettle, however, would seem to possess 

 other means of protection in its strong scent and rough hairs. 



The following are instances from the British flora of groups of 

 plants belonging to different orders yet possessing a general simi- 

 larity in appearance corresponding to a similar mode of life : — 



1. A very striking group of plants is that of the leafless root- 

 parasites, represented in the British flora by the species of broom- 

 rape {Orohanche) and the toothwort {Lathraa Sqmmaria), belong- 

 ing to the order Orobanchaceae ; by the yellow bird's-nest [Mono- 

 tropa Hypopitys), of the order Ericaceae ; and by three species 

 of Orchid, viz., Neottia Nidus-avis, Corallorhiza innata, and Epi- 

 pogiian aphylhim, the two latter very rare in Britain but commoner 

 in Central Europe, specimens of the last named from Switzerland 



