28 VEGETATION IN COLORADO-HOLM. [memo^snat .osat, 



poorly represented, only three species having been described, so far, viz, A. dioica (L.) Gartn., 

 A. alpina (L.), R. Br. and A. Carpathica (Wahlenb.) R. Br., besides a fourth one, but imperfectly 

 known, from Australia. Of these Old World species A. dioica has been found only once on this 

 continent ''in woods at Providence, Rhode Island, by Geo. Thurber in 1844, " 27 while the two 

 others have been reported from many stations in the north, from Labrador and westward to 

 Bering Strait, and according to Gray, 28 southward on the high mountains to Colorado, California, 

 and New Mexico. By John Macoun 2 ° A. alpina and Carpathica are recorded from a number of 

 stations from Labrador to Alaska, and especially from the Rocky Mountains. 



However, according to the recently published floras of the Rocky Mountains, by Aven 

 Nelson 30 and P. A. Rydberg, 31 neither A. alpina nor A. Carpathica are credited to the United 

 States, but only A. pulcherrima (Hook.) Greene, formerly considered a variety of A. Car- 

 pathica; nevertheless 43 species are recorded by Rydberg, and 21 by Nelson. A. pulcherrima 

 inhabits prairies and marshy meadows in Canada, and occurs also in the Rocky Mountains, but 

 only at lower elevations, being frequent in the aspen zone near Longs Peak. A. Carpathica 

 and A. alpina, on the other hand, have been reported from the summits of the most elevated 

 Rocky Mountains in Canada, and we should naturally expect that they had also found their 

 way southward to Colorado. However, the former of these, A. Carpathica, is a plant of 

 such characteristic aspect that it could hardly have been overlooked or confounded with any 

 of the other species, while the latter does resemble some of the narrow-leaved species. 



Antennaria alpina (L.) R. Br. 32 is quite a variable plant with respect to the outline of the 

 leaves, their covering with tomentum, the development or absence of stolons above ground, and 

 the composition of the inflorescence. The Colorado plant represents the variety canescens 

 Lge., 33 and it seems indeed as if this variety is the predominant in North America, but it has also 

 been recorded from Greenland and Scandinavia. In some of the specimens from Colorado the 

 leaves are somewhat broader than in the Old World representative, but the structure of the 

 involucre is the same, and altogether my material can not be distinguished from this species. 

 I observed no specimens of the staminate plant, which, as we know, is extremely rare, and has 

 so far been recorded from only a very few stations in Scandinavia, France, and Alaska. The 

 Alaskan staminate plants were of the variety monocephala D C. The species is widely dis- 

 tributed throughout the boreal regions of both worlds, but it is absent from Spitzbergen, and 

 is replaced by A. Carpathica (Wahlenb.) R. Br. on Nova Zembla. The occurrence of A. alpina 

 in Greenland, where it is very frequent, and in Alaska, is a fact that speaks in favor of its pres- 

 ence in the Rocky Mountains, like so many other Arctic, and especially circumpolar, species, 

 although several authors are unwilling to accept it south of the American Arctic coast. 



The genus Senecio is well represented in the Alpine region, and most of the species are 

 confined to Colorado. It is a very striking assemblage of Alpine species, very distinct from 

 those of the Old World at similar altitudes, and the Rocky Mountains altogether constitute a 

 most important center of development and distribution of the genus. Although occurring at 

 very high elevations in Colorado, the species are remarkably robust and tall, in this respect 

 surpassed only by Actinclla grandifiora Torr. and Gr. 



Campanula rotundifolia L. 



The typical species does not occur in Arctic America, but is replaced there by the 

 variety arctica Lge., reported from "Canada and Labrador to the Arctic regions" (Gray). 

 Another form is Alaskana Gray from the northern Aleutian Islands to Sitka and Kodiak. 

 The typical species, on the other hand, is widely distributed on this continent, and Gray (1. c.) 



87 Gray's new manual of botany, seventh edition, p. 820. 



'8 Synoptical flora of North America. Gamopetalae. Washington, 1SS8. P. 232. 

 "Catalogue of Canadian plants. Montreal, 1SS4. P. 236. 

 *> New Manual of Botany of the Rocky Mountains. 1909. 

 31 Flora of the Rocky Mountains and adjacent plains. New York, 1917. 



33 Porsild, M. P.: On the genus Antennaria in Greenland. (Medd. om Greenland. II. Copenhagen, 1915. Holm, Theo.: Antennaria alpina 

 and A. Carpathica. Rhodora, vol. 22. 1920. 



» Flora Danica XLVn, Tab. 2786. Kobenhavn, 1868. 



