Arctic Plants: Geographical Distribution 125 b 



Ameiican continent where it is widely distributed from Labrador and Hudson 

 bay to the alpine and sub-alpine Rocky mountains, extending south to the 

 borders of New Mexico, west to British Columbia, and south in the Sierra Nevada 

 to King's river in California. 



Typical P. palustris does not occur on this continent but is represented by 

 the variety Wlassoviana Bunge, "floribus minoribus galea rectiuscula obtusa," 

 a native also of Baikal and Davuria; on the other hand, the type does occur in 

 the arctic regions outside of America but is much more common farther south 

 where it evidently developed; thus the species illustrates a case of two geographic 

 centres, both south of the arctic region, from which two forms developed but 

 modified to such a small extent that they can be considered only as forms of one 

 Species. 



The smaU family Selaginaceae is in the arctic region represented by the 

 genus Lagotis Gaertn. (Gymnandra Pall.); the genus comprises, according to 

 Bentham and Hooker, eight species which are natives of Central Asia, some of 

 which extend to the arctic regions. In North America L. glauca Gaertn. with 

 the variety Stelleri (Cham, et Schl.) is credited to Alaska and adjacent islands. 

 While the variety has been reported from several stations in arctic Siberia, from 

 St. Lawrence bay (Kjellman) to Ural, it seems to be very rare in Russia: "Terra 

 Samojedorum versus cacumen mentis Sorolop. in vicinia promontorii Mikulkin 

 (Ruprecht)," and it is absent from Scandinavia, Greenland, and the arctic 

 American archipelago. The genus must be of Asiatic origin. 



Valeriana capitata Pall, and V. officinalis L. are the only species of the 

 genus which have been found in the arctic regions; of these the latter does not 

 grow in America except as an escape from gardens. V. capitata, on the other 

 hand, is by Macoun (Catal. I.e.) recorded from cool woods and by brooks, 

 generally in the mountains and on the arctic shore; it is rare in arctic Russia, 

 and with regard to Siberia Kjellman gives the distribution as follows: Konyam 

 Bay, St. Lawrence Bay, Terra Tschuktschorum, Kolyma River, mouth of the 

 River Olenek and Lena, Tajmyr River, and the mouth of the River Jenisej; it 

 occurs also in Caucasus, Altai, and Baikal. As a species it occupies a somewhat 

 isolated position in Russia and Siberia since the nearest allies are natives of 

 southern regions, notably Caucasus. 



On this continent there are four species in the northern Rocky mountains 

 two of which, V. uliginosa and V. sitchensis, may be considered as close allies; 

 it would thus appear as if the genus has a centre of distribution and develop- 

 ment on this continent located in the northern Rocky mountains. In the Old 

 World, Caucasus with its nine species, four of which are endemic, must consti- 

 tute another centre, and the fact that V. capitata is among the species indigenous 

 to. these mountains might indicate that the species has had a dual origin; it 

 certainly would be difficult to combine these two centres with each other, not 

 only on account of the great distance, but also on account of the very distinct 

 element developed in these mountains. 



Of the 230 species of Campanula recognized by Bentham and Hooker, 

 "per hemisphaerium boreale late dispersae, in regione Mediterranea imprimis 

 orientali copiosissimae," some few have spread to the arctic regions; among 

 these Campanula uniflora is recorded from latitudes as far north as 79° on 

 Spitzbergen (Eaton); 76° 7' on the west coast of Greenland, Cape York (Nathorst), 

 and 74° 40' on the east coast (Dus6n). However, the fact that, so far, only four 

 species have been recorded from the arctic regions seems surprising when we 

 consider the distribution of the genus in Europe, in the mountains of Central 

 Europe and Caucasus especially. For in the mountains of Switzerland, Austria, 

 and Germany not less than 21 species are indigenous, several of which are alpine; 

 and with regard to Caucasus 20 species have been recorded from these mountains, 

 11 of which are endemic. But as indicated above, the Mediterranean region 



