ARCTIC PLANT GEOGRAPHY 1 45 



hand, H. W. Henshaw^ believes that birds are the most important 

 of nature's seed carriers, for viscid and hooked seeds become attached 

 to their plumage and in mud attached to their feet and feathers. The 

 writer agrees with Professor Henshaw. He has seen robins eat pin- 

 cherry fruits (Prunus pennsylvanica) and void the undigested stones. 

 He has seen the tree swallow eat the fruits of the bayberry {Myrica 

 carolinensis) and void the fruits, minus the waxy coat; and crows 

 are responsible for the wide distribution of the poison ivy. Simmons^" 

 recognizes birds as a factor in plant dissemination, and he believes 

 that the ptarmigan, which is non-migratory but roams much about, 

 is responsible for the spread of the Arctic plant species that have 

 edible fruit. He considers the wind, however, as the prime distributing 

 factor, and with this conclusion the recent work of Ostenfeld agrees 

 (see, above, footnote 6)^^ Of 204 species of plants from the American 

 Arctic Archipelago he found that the majority were wind-distributed, 

 as follows :^^ 



Plants Disseminated by Wind 



Having seeds or fruits with flying apparatus 86 species, i. e. 42% 



Having light seeds and achenes 95 " " 47% 



Having spores 8 " " 4% 



189 species, i. e. 93% 

 Plants Disseminated by Other Means 

 Having heavy seeds (dispersal by wind possible) ... . 5 species, i. e. 2% 

 Having berries and drupes (dispersal by birds, especially 



ptarmigan) 4 " " 2% 



Dispersal by vegetative propagation alone 6 " " 3% 



15 species, i. e. 7% 

 The whole subject of Arctic plant dispersal needs further study. 



Method and Rate of Vegetative Multiplication 



The morphology of Arctic plants has been investigated by a num- 

 ber of students (Warming and his colleagues, ^^ Holm,^* Rikli^^), and 



9 H. W. Henshaw: Our Mid-Pacific Bird Reservation, Yearbook U. S. Dept. of Agric. for igii , 

 Washington, 1912, pp. IS5-164; reference on pp. 156-157. 



>» H. G. Simmons: A Survey of the Phytogeography of the Arctic .\merican Archipelago, With 

 Some Notes About Its Exploration, Lunds Univ. Arsskrift, N. S., Section 2, Vol. 9, No. 19, Lund, 

 1913; reference on pp. 145-151'. 



11 In the comprehensive work on the action of wind in northern latitudes by Carl Samuelsson 

 (Studien iiber die Wirkungen des Windes in den kalten und gemassigten Erdteilen, Bull. Geol. Insin. 

 Univ. of Upsala, Vol. 20, pp. 57-230, Upsala, 1927) a major section (pp. 1 18-168) is devoted to the 

 action of wind on vegetation, including the distribution of plants in the Polar Regions and on high 

 mountains. 



1- ibid., p. 148. 



w Eugenius Warming et al.: The Structure and Biology of Arctic Flowering Plants, Meddelelser 

 om Gr0nland, Vols. 36 and 37, 1912 and 1921. 



1* Theodor Holm: Contributions to the Morphology, Synonymy, and Geographical Distribution 

 of Arctic Plants, Report of the Canadian Arctic Expedition, 1913-18, Vol. 5: Botany, Part B, Ottawa, 

 1922, with bibliography. 



15 Martin Rikli: Zur Kenntnis der arktischen Zwergstrauchheiden, Vierteljahrsschr. Naiurf. 

 Gesell. in Zurich, Vol. 61, 1916, pp. 231-248. 



