Introduction. 5 



forms, of which we found several, each occupying well- 

 defined small areas, and apparently possessing definite 

 characters. But, as more and more of the patches were 

 examined, these distinctions were found to melt away ; for 

 each fresh patch yielded a slightly different form, so that 

 finally we were able to obtain a nearly complete series of 

 intermediates seeming to connect the extreme .S". umbrosa 

 with the extreme 5. Geum, all of them living within a 

 small area under similar conditions. Pinguicula vulgaris 

 and P. grandiflora, on the other hand, we found growing 

 together in abundance, and quite distinct except at one 

 spot where, below a rock on which both grew, we found a 

 number of hybrids. In this case the allied forms, some- 

 times only ranked as sub-species, are both good species, and 

 have different geographical distributions, though they over- 

 lap at more than one point. Botanical books are full of 

 similar anomalies, often due to a natural desire to announce 

 the discovery of a form new to Britain ; but for the student 

 of geographical distribution varietal names founded on 

 such material are worse than useless. For they tend to 

 confound sub-species, which, if found in isolated areas show, 

 in all probability, a transportation of the seeds from one 

 to another, with varieties or forms, which will reappear 

 wherever the parent species is subject to particular con- 

 ditions. 



A flora like that of the British Islands may be studied 

 in so many different ways, that it will be well to define at 

 once the standpoints from which it is viewed in the following 

 pages. I do not propose, nor do I feel competent, to 

 touch on the questions of the evolution of the species, or 

 of their relationship to each other ; what will be attempted 

 in Chapter II. is, to give a sketch of the existing flora as 

 a whole, to note its composition, and the distribution of 

 the species. Chapter III. will deal with the means of 



