236 ANNALS OF SCOTTISH NATURAL HISTORY 



With regard to the question of habit and development. 

 In EupJirasia these are easily affected by a slight change in 

 the nature of the habitat ; and until it has been shown that 

 any variation in development is innate to the plant, and not 

 merely a temporary state induced by an altered environment, 

 it is futile to put it forward as a distinguishing character. 



Euphrasia borealis is widely distributed and pretty 

 common in Shetland. The normal state affects lowland 

 pastures and is a rather large-flowered, moderately branched 

 plant, similar to Townsend's plate (" Journ. of Bot," 1897, 

 fig"- 374)- When, however, it gets a little way up the lower 

 hill slopes into drier and more exposed situations, its aspect 

 is entirely changed. It becomes a dwarf (3-7 cm.), densely 

 bushy, much branched plant with smaller flowers. On the 

 other hand, the far less common state sometimes found in 

 very wet peat bogs shows the opposite extreme. Here we 

 get a plant which reaches a height of 32 cm. with a stem 

 often quite simple or with but one pair of short branches 

 placed low down, or more rarely with two or three pairs. 

 The flowers are perhaps the largest of all, the lower lip 

 measuring sometimes as much as i cm. in length. 



Do these three phases represent true varieties or species ? 

 Or are they merely the temporary effect of changed environ- 

 ment? I do not know, nor is it possible to find out except 

 by making careful experiment and growing the three plants 

 under like conditions. But it is right to treat them simply 

 as states, until the contrary has been proved, rather than 

 adopt the practice of first describing your variety at all 

 hazards, and leaving it to others to find out whether it is 

 really distinct or not, if and when they can. 



Although Prof, von Wettstein made many valuable 

 cultural experiments, something still remains to be done 

 with regard to the British-born names. A few experiments 

 carefully conducted on right lines would put us in possession 

 of facts in place of opinions. The experiments most needed 

 are the following: — (i) To grow the disputed forms say 

 E. minima, E. scottica, and E. foulaensis side by side under 

 equal conditions, which of course involves growing them all 

 on the same host-plant ; and (2) to take the seeds from a 

 plant of either E. minima or E. scottica and sow half of them 



