LINIJEAJf SOCIETY OF LOXDOIN'. 8 1 



A Cartographic Study o£ the Southern Element in the British 

 Elora. (With 11 Maps, on Plates 1-5). By O. Staff, 

 F.E.S., F.L.S. 



[Kead 6th April, 11)16.] 



Three years ago I published an analysis of the " Southern Ele- 

 ment " in the British Elora *, supported by tables enumerating 

 tlie species classed under that Iieading, and indicating their dis- 

 tribution in Great Britain and Ireland and also their northern 

 limits on the Continent. It \A'as obvious from the beginning that 

 the addition of maps would greatly help in visualising the results 

 obtained. However, there was no time then for preparing them. 

 This lias since been done, and the present paper is offered as an 

 adaptation of the earlier essay to cartographic illustration. The 

 introductory part of the paper has been taken over almost 

 verbatim, whilst the tables and the paragraphs explaining them 

 were elimiuated. The remainder has been I'ecast and connected 

 with the maps. This, however, has not led to any modification 

 of the conclusions arrived at originally. In fact, although the 

 subject has been under the notice of British botanists for three 

 years and I myself have constantly had my eye on it, no cor- 

 rections of more than subordinate detail have been suggested. 

 Only two of them need be mentioned. A revision of the British 

 Atropis has convinced me of the identity of A, festuca'formis from 

 Co. Down, Ireland, with A. Foucaudii, which therefore takes its 

 place in the tables of my original paper as an Atlantic species. 

 Material submitted by Mr. G. C. Druce has greatly assisted me 

 in clearing up that point. The other detail is the elimination of 

 Allium triquetum which I had put down as doubtfully indigenous, 

 but consider now as an alien. This removes one of the Mediter- 

 ranean elements. Neither of these corrections affects the carto- 

 graphic illustrations, and only to a negligible degree the 

 percentages and proportional figures. 



The map used for the illustrations was designed for me on 

 my instructions by Messrs. Sifton, Praed & Co. It combines 

 Watson's " vice-counties " of Great Britain, as numbered in the 

 last edition (1908) of the ' London Catalogue of British Plants,' and 

 Praeger's " divisions " of Ireland (' Irish Topographical Botany,' 

 1901). To show the distribution on the Continent an inset map 

 of Europe was added. The procedure in construing the general 

 maps (1-3) was this. The distribution of each species considered 

 as " Southern " was entered in a separate map, then the number 

 of species in each vice-county or division counted under the head- 

 ings " Southern," " Atlantic," and " Mediterranean," and the 

 percentages represented by them on the totals of " Southern," 

 "Atlantic," and Mediterranean" species computed. Finally, 



* 0. Stapf. "The Southern Element in the British Flora," Engler's 

 Botanische Jahrbiicher, Bd. 1. (Supplementband) pp. 509-525. 



LINN. see. PEOCEEDINGS. — SESSION 1916-1917. g 



