206 Rhodora [SEPTEMBER 
The southern extension of A. Filix-femina into the western United 
States is marked by a peculiar technical variety, as seems often to be 
the case with northern plants which extend south into California and 
the southern Rocky Mountains. 
The Filix-femina group of the genus Athyrium presents a typical 
case of boreal distribution. Apparently the center of this distribution 
is somewhere in Asia. Christ says of the genus Athyrium in China, 
“The variation of the genus Athyriwm in southern China is only 
equalled by that of the same genus in Japan and the Indian Himalaya, 
other countries belonging to the same botanical region... .It is a 
plastic mass which appears to be endlessly modified.' 
On the other hand the number of species of this genus in North 
America is limited to those just described and the two diplazioid 
species A. acrostichoides and A. angustifolium. 
Moreover, as has been pointed out already, the Diplazia of tropical 
America, presumably descendents from the genus Athyrium, though 
very numerous as to species, appear to belong almost wholly to a 
section of the genus which is probably descended from Athyriwm 
acrostichoides (Sw.) Diels or some very similar species, while the Asiatic 
Diplazia form a mass of species of almost endlessly complicated rela- 
tionships. 
Athyria of the true Filix-femina group extend south into the tropical 
mountains in Mexico (A. Martensi and A. Domber Desv.), and 
the strong relationship of the boreal flora of the Selkirk Range with that of Scandinavia. Evi- 
dence is accumulating, that this relationship extends to parts of the flora which cannot be 
considered as arctic-alpine, but rather cool temperate and subalpine. 
The lady fern is only one of numerous cases in which plants of cool temperate Europe occur,, 
in precisely the same form, in the cool and moist evergreen forests of British Columbia and 
Alaska. 
The occurrence of Athyrium alpestre in the mountains of western America,— in this case in a 
somewhat modified form,— is another instance of the relationship of European and north-west 
American floras, though in this case the plant is distinctly alpine in character. The further 
extension of its range to the Gaspé region is entirely in keeping with the known facts concern- 
ing the flora of that interesting region. See Fernald, M. L., The Soil Preferences of Certain 
Alpine and Subalpine Plants. Ruopora, ix. 149 (1907). 
The Reappearance of the variety sifchense in the western part of the Selkirk Range, is also. 
entirely normal. Piper, in his Flora of Washington, Contrib. from the U. S. National Herb. 
xi. 53 (1906) called attention to the large number of west coast plants, which do not occur in 
the interior of Washington, but which reappear in the more moist hill country of eastern Wash- 
ington and northern Idaho. Evidence is accumulating that a much larger number of coastal 
forms occur farther north in the region around Revelstoke, the interior region, which, above alk 
others, has the nearest approach to the coastal climate. 
1 La variation du genre Athyrium en Chine mérid. n’a d’égale que celle du même genre au 
Japon et l Himalaya indien, pays du reste qui appartient à la même région botanique.. . . . C’est 
une masse plastique qui semble se modifier sans cesse. Christ, H. Les collections de Fougères. 
de la Chine au Museum d’histoire naturelle de Paris. Bull. Soc. Bot. de France lii. Mém. i. 
50 (1905). 
