72 HISTORY OF BOTANY. 



(floating, alluding to the leaves). Tliere are other names, 

 referring to the duration of the species; as Mercurialis 

 perennis (perennial), M. annua (annual) : and to the situa- 

 tions in which they grow ; as Myosotis palustris (swamp), 

 Vicia sepium (of hedges) : or the time of flowering ; as Scilla 

 verna (spring), Leucoium jestivum (summer) ; and in fact 

 anything will serve for a good trivial name provided that it 

 is correct, but generally those founded on the colour; of the 

 flowers are not good, because it is a variable feature, thus 

 Digitalis purpurea (purple foxglove) has very commonly 

 white flowers, and the gardeners' name of "Digitalis 

 purpurea alba" shows the absurdities such names would 

 lead us into. There are many similar cases : I will instance, 

 in the British Flora, Viola lutea (yellow violet). Now, accord- 

 ing to high authority,* this species is not necessarily yellow.f 

 Then again Milkwort (Polygala vulgaris), though generally 

 blue, we frequently find red, white, and blue, in the compass 

 of a few yards, and to have called it ceerulea would have 

 been to give it a bad specific name. 



The same may be said of Poor-man's Weatherglass 

 (Anagallis arvensis), which is met both with pink and blue 

 flowers, the two sorts being formerly called mas ^nd fcemina 

 (male and female) ; we have also Greek Valerian (Polmonium 

 cseruleum), both white and blue; and the same with our 

 common Blue-bell. So the colour of flowers must be taken 

 as a bad specific distinction, and if, as in the case of 

 Anagallis, specific distinctions are believed to exist, they 

 should be founded on other characters than colour. 



'•■ Bentham. 



f Though I have seen this plant growing in such profusion as to 

 attract the attention of ahnost every passer by, as, for instance, 

 between Chapel en-le-Frith and Castleton in the High Peak, and 

 between Aberystwith and the Devil's Bridge, all yellow, I have fre- 

 quently met with parti-coloured flowers that I could not refer to any 

 other species. 



