NEW PflYTOIiOGIST. 
Vol. XI, No. 2. 
February, 1912 . 
[Published February 29th.] 
THE DISTRIBUTION OF THE FLORA IN THE 
ALPINE ZONE. 1 
By Paul Jaccard, 
Professor at the Federal Polytechnic , Zurich. 
[With Two Text-Figs.] 
JHE botanising hitherto done in the Alps gives us but very 
imperfect information on the local distribution of the alpine 
flora. Attention has been specially directed to rare plants, whose 
least localities are recorded, while the common species are often 
neglected. But from the standpoint of the factors which regulate 
distribution the common species are the most important. The rare 
species of the alpine flora, those which appear only in a few isolated 
stations, sometimes only in a single one, are usually either species 
with a very sporadic general distribution, or they are endemic 
species, or finally they may be “glacial relicts.” All these 
categories are of great interest from the standpoint of the history 
of floras ; their presence in the stations which they now occupy is 
explained not only by the ecological conditions they find in these 
stations, but also by historical causes, and especially by the 
conditions of post-glacial immigration. 
r This article is translated from the French original (which 
appeared in the Revue generate des Sciences, 15th December, 
1907, pp. 961—967) and published in The New Phytologist 
(by hind permission of M. Olivier, the editor of the Revuege'ne'rale) 
at Professor Jaccard’s request. The Editor acceded to this 
request the more readily, inasmuch as the statistical 
method employed by Professor Jaccard appears worthy of 
being tested over a wider range of vegetation. With 
suitable development, these and similar statistical methods 
promise to form an important means of connecting the study 
of floristic distribution with that of the determination and 
distribution of units of vegetation.— Editor, New Phyt. 
