52 INTRODUCTORY EXPLANATIONS. 



somewhere between a fifteenth and a twentieth part of the 

 flora of Britain. As examples, we have Sinapis monensis, 

 Matthiola sinuata, Raphanus maritimus, Sedum anglicum, 

 Cotyledon Umbilicus, Bartsia viscosa, Pinguicula lusitani- 

 ca. Euphorbia Peplis, Euphorbia Portlandica, Scirpus 

 Savii, — which occur in several counties ; also Sibthorpia 

 europaea, Erica vagans, Erica ciliaris, Physospermum cor- 

 nubiense, Polycarpon tetraphyllum, Adiantum Capillus- 

 Veneris, Cynodon Dactylon, and others which occur in 

 very few or only single counties. On pages 9 and 12, 

 Cynodon Dactylon is inadvertently said to be found only 

 in Cornwall ; that name having been overlooked in Dr. 

 Salter's list of plants near Poole, in Dorset : a conse- 

 quence of its alphabetical series of names, which renders 

 comparisons with scientifically arranged lists so exceed- 

 ingly troublesome. 



7. A Local or doubtful Type. — Interspersed about the 

 island, there are some species whose distribution is re- 

 stricted to single or {ew counties. Such species can sel- 

 dom show that decided tendency to the east or the west, 

 to the south or the north, to the mountains or otherwise, 

 which would fully warrant their assignment to any one of 

 the six preceding types of distribution. In those instances 

 where the single or few localities occur clearly and solely 

 within the geographic limits of one of the types, the plants 

 will usually be associated with the group to which they 

 thus make the nearest approach. For instance, there can 

 be no hesitation in assigning the extremely local Lychnis 

 alpina and Oxytropis campestris to the Highland type ; 

 and not much more doubt can arise respecting the pro- 

 priety of placing Arenaria norvegica and Primula scotica 

 in the Scottish type. So also, the local Cicendia filiformis 

 may go to the English type ; Veronica verna, to the Ger- 

 manic type ; Erica vagans, to the Atlantic type. But after 



