188 WORLD-DISTRIBUTION OF THE BRITISH CARYOPHYLLACEif:. 



the iiiouiitinns of Central Europe (usually also to nortliern Asia), 8. — 

 Silene acanlis, LycJmis alplna, Sagina saxatilis, S. suhulata, Arenaria 

 uliffinosa, Stellaria cerastoides, Cerastium alpinum, C. latifolium. 



7. Like the last, but not reachina: America, 0. 



8. Boreal, but not reaching the mountains of Central Europe, 3. — 

 Sagina tiivalls, Arenaria norvegica, A. rubella. 



9. Plants of the mountains of central, but not of Northern Europe, 

 1. — Cherleria sedoides. 



Total number of species, 59, out of which 12 are characteristically 

 boreal or montane. 



Passing these data in review, the following, it seems to me, are some 

 of the most noteworthy points for consideration which they suggest. 



1. The wide area of dispersion which the species, taking them as a 

 whole, possess. Nearly one in four of them takes rank in the first 

 group ; less than one in four is confined to Europe; and the five which 

 are least widely dispersed, are spread over a wide area on the continent. 

 (In considering this point, it should be remembered that 22 species 

 out of the 59 are annuals, and the other 37 all herbaceous perennials, 

 and that the Natural Order furnishes an extreme instance of what has 

 just been alluded to, and consequently is not fairly typical for the Bri- 

 tish flora, taking it as a whole.) 



2. That these 59 species can be traced over such a wide area of dis- 

 persion (more than half of them, be it remembered, are cosmopolitan 

 for the north temperate zone, and this zone includes in round numbers 

 half the land-area of the globe) without losing their distinctive indi- 

 viduality(meaning by this, that allowing a very small margin, I feel 

 confident, that, casual errors excepted, any one who has written on 

 botany in Britain would, upon examination of the specimens, accept 

 the plants here regarded as identical, as being really and absolutely so 

 throughout their range as stated, and not refer them even to difi'erent 

 subspecies or varieties). 



3. That out of the 14 species, common to the north and south tem- 

 perate zones, 8 are annuals, most of them being' common weeds of cul- 

 tivated ground, that 2 others are maritime plants, but that with regard 

 to, at any rate, 3 out of the rest, Cerastium arveiise, Sagina procumbens, 

 and Stellaria glauca, there can be no reasonable ground for suspicion 

 that tliey owe their area in the southern hemisphere to human inter- 

 vention. 



