4 Origin of the British Flora. 



have had but slight opportunity of studying. This has 

 especially been the case with regard to the lacustrine 

 deposits of the Scottish Lowlands, so minutely examined 

 by Mr. James Bennie. The results of these investigations 

 will be found summarised in Chapters IV. and V. of this 

 work. 



In the examination of our recent flora I have looked 

 at the plants mainly from the point of view of the field- 

 naturalist. Their climatic and geographical distribution ; 

 the periods of ripening, and the means of dispersal of their 

 seeds ; their competition with other plants ; and their 

 dependence on, or destruction by animals, were the circum- 

 stances especially noted — more so than critical distinctions 

 of varieties and sub-species. Not that these distinctions 

 are considered unimportant, but mainly because of the 

 difficulty of studying them without a complete herbarium, 

 too heavy to transport during constant changes of station. 

 Moreover, botanists have almost ignored the essential 

 distinction between a varietal form due to local conditions, 

 and a true sub-species or race ; for many of our named 

 sub-species have evidently no more claim to such rank than 

 have luxuriant garden specimens. Forms, for instance, of 

 the water-crowfoot {Ranunculus aquatilis) or of the lesser 

 spearwort {R, Flammuld) growing in a well-manured horse- 

 pond or ditch have no claim to rank as sub-species, unless 

 they can be found also under more natural conditions, and 

 come true from seed. Again, the prostrate maritime form 

 of broom found in Cornwall {Cytisus scoparius, var. pro- 

 stratus) has similarly no claim to varietal rank, for Mr. 

 Mitten tells me that seeds gathered by him grew in his 

 garden into the common erect form of broom. A botanical 

 visit to the Dingle Promontory, in Kerry, in company with 

 Mr. Edmund Baker, produced several instances of this 

 sort. We examined Saxifraga umbrosa and its allied 



