academ, of sciences.] CENTERS OF DISTRIBUTION. 31 



Gentiana frigida Hnke. 



Originally described from specimens collected " in alpibus Styriae et in Carpathis," the species 

 has also been reported from "terra Tschuktschorum ad sinum St. Laurentii," and, furthermore, 

 from the Alpine region of the Rocky Mountains in Colorado, Utah, and Montana. By Ledebour 3i 

 the (European) specific name frigida Hnke. is reserved for the European plant, while the other, 

 from St. Lawrence Bay, is described as a new species, G. Romanzowii Ledeb. However, in 

 Flora Rossica, 35 Ledebour himself enumerates the latter as a variety Romanzowii of G. frigida 

 Hnke., a disposition already proposed by Grisebach. 36 As compared with these, the plant 

 from the Rocky Mountains is somewhat variable in accordance with the altitude of the stations, 

 but I find no distinction by which the American plant may be separated from the European. 

 According to Kjellman (1. c, p. 507), typical G. frigida Hnke. does occur in Arctic Siberia — 

 St. Lawrence Bay, Arakamschetschene Island — besides Nischne Kolymsk, northern Siberia. 

 In other words, we have before us a species of which the geographical distribution is extremely 

 local: The Carpathian Mountains in Europe, the northeastern part of Siberia, St. Paul and 

 Shumagin Islands off the north coast of Alaska, and the Rocky Mountains. At present the 

 species is very rare in Europe and Asia but quite frequent in the Alpine region of the Rocky 

 Mountains, a fact that may indicate two distinct centers of development and geographical 

 distribution unless we admit the possibility of a former, much wider range, but broken by 

 the local extermination of the species. A similar wide and relatively scattered distribution 

 is also noticeable in some of the other gentianaceous plants, which I collected in the Rocky 

 Mountains, but mostly at lower elevations. Of these may be mentioned: Gentiana tenella 

 Rottb., G. humilis Stev., G. prostrata Hnke., Swertia perennis L., and Pleurogyne rotata Griseb. 

 all of which are known, also, from Eurasia. Of these the geographical range is as follows: 



Gentiana tenella Rottb.: Scandinavia, including the Arctic region; Iceland; Alps of Switz- 

 erland and Tyrol; Arctic Russia; Arctic Siberia; Altai and Baikal Mountains; the Himalayas; 

 Alaska. 



G. humilis Stev. : Caucasus ; Ural ; Altai and Baikal Mountains ; and the Himalayas. 



G. prostrata Hnke.: Alps of Tyrol; Caucasus; Altai and Baikal Mountains; Asiatic coast of 

 Bering Straits; Alaska. 



Swertia perennis L. : Alps of Germany and Switzerland; middle and south Russia; Caucasus; 

 Altai Mountains; Alaska. 



Pleurogyne rotata Griseb.: Iceland; Arctic Russia; Altai and Baikal Mountains; Labrador 

 and Hudson Bay to the high northwest coast and Kotzebue Sound ; Greenland. 



Similar to Gentiana frigida Hnke., these plants are mainly inhabitants of mountains. 

 G. tenella Rottb. is almost circumpolar, and Pleurogyne is well represented in the northern and 

 Arctic regions. The original geographical center of these two plants may thus have been 

 located in the Arctic mountains. On the other hand, a more southern center may be attributed 

 to G. humilis Stev. and G. prostrata Hnke.; for instance, the Baikal and Altai Mountains. 

 With regard to Swertis perennis L., so widely distributed throughout middle and south Europe, 

 I presume the species originated there, while the variety obtusa (Ledeb.) represents the plant as 

 it occurs in South Russia, Siberia, and the Rocky Mountains. In Siberia, the Altai and Baikal 

 Mountains constitute a most important geographical center of a number of plants, notably 

 northern or even Arctic species, and it seems strange that Gentiana frigida Hnke. has not so 

 far been discovered in these mountains. There is, however, a species called G. algida Pall. 

 which is known from there as well as from eastern Siberia, and is a close ally of G. frigida 

 Hnke., so close, indeed, that several authors have considered G. algida as merely a variety 

 of G. frigida. 



a * In A. de Bunge: Conspectus generis Gentianae imprimis specierum Rossicarum 1824. P. 215. 



«Vol. 3. 1845-1851. P. 65. 



»« Genera et species Gentianearum. Stuttgart 1839. P. 279. 



106023°— 23 3 



