48 ECOLOGY, PLANT GEOGRAPHY [Bot. Absts., Vol. IV, 



Hawaiian flora is sufficiently evident. Not only is the number of extra-American genera 

 common to the two regions very large, but a majority of the endemic genera are evidently 

 derived from southern Pacific or Asiatic types." — The American elements are of two kinds: 

 first, those which have been introduced since the isolation of the islands, mostly from the 

 west coast of North America, through the agency of wind or of migratory birds; and, second, 

 certain genera allied to South American types which very possibly may be residual forms from 

 an era when there was a connection between South America through some extensive Antarctic 

 continent with New Zealand." — An objection to the continental theory has been the absence 

 of Coniferae, expecially such southern types as Araucaria, Podocarpus and Agathis, and other 

 old types which are abundant in the Australasian-Malayan region. "The probable explana- 

 tion is the possibility of the extinction of these forms after the isolation of the islands. There 

 are plenty of examples of such disappearances of plants from regions which they once inhab- 

 ited." These extinctions may have been brought about by various causes such as diseases 

 and climatic changes. "The almost complete absence of granitic or calcareous soils, for 

 example, would practically prohibit the growth of many species that might very well have 

 been present at an earlier period before the submergence of areas now completely covered 

 by volcanic formations." Detailed accounts of the animals give strikingly similar results; 

 especially is this true among the molluscs, insects, arachnida, marine invertebrates, and fishes. 

 [See also Bot. Absts. 1, Entry 822; 3, Entry 1608; also Plant World 22: 57. 1919.]— LeRoy 

 Abrams. 



320. Cheeseman, T. F. The vascular flora of Macquarie Island. Sci. Rept. Australian 

 Antarctic Expedition of 1911-14. C7:63p. Pt.3. Map. 1919.— Lying 600 miles south-west 

 of the Island of New Zealand, 920 miles south-east of Tasmania and 970 miles from the Ant- 

 arctic continent, the position of Macquarie Island is one of great isolation. It is little more 

 than a short range of mountains with peaks ranging from 900 to 1424 feet in height, the length 

 of the island being 21 miles and its breadth less than 4 miles. The hills descend rapidly 

 towards the sea forming bold headlands and precipitous cliffs with no harbors or sheltered 

 bays. It possesses a remarkably equable temperature, the mean maximum being 43\5F. and 

 the mean minimum 37°. 9F. while the extreme range is only 24°. 8F. A rainfall of 45 inches is 

 distributed so that no month has less than 3 inches. Wind velocity is uniformly great, averag- 

 ing 18 miles per hour. It has an impoverished vascular flora of 30 seed plants, 3 ferns and 1 

 lycopod. Concerning the origin and affinities of this flora Cheeseman decides that with the 

 exception of three endemic grasses it dates no further back than the last glacial epoch. The 

 repopulation was probably effected through the agency of birds as half its plant species are 

 common to New Zealand, 15 are found also in Fuegia or South Georgia, and a like number are 

 circumpolar. — The vegetation is characterized by the entire absence of trees and shrubs. 

 The conspicuous plant forms are the tussock grasses, principally Poa foliosa, the large 

 leave 1 "Macquarie Island cabbage," an araliaceous plant resembling a fine rhubarb, the 

 cushions of the umbelliferous Azorella Selago, globular masses often four feet across, and a 

 purple composite, Pleurophyllum Hookeri, with long sage-green leaves. The tussock grass 

 is by far the most important of these forms occupying much of the mountain slopes. Rev. by 

 Fuller in: Bot. Gaz. 69: 95. 1920. Other reviews in: Nature 104: 101. 1919. Jour. Botany 

 57:262. 1919. Plant World 22 : 184. 1919.— Geo. D. Fuller. 



321. Clute, Willard N. A trip to Navajo Mountain. Amer. Bot. 25:81-87. PL 1. 

 1919. — Navajo Mountain on the borders of Arizona and Utah has never been visited by bot- 

 anists. The surrounding desert has few species of flowering plants, but the mountain above 

 7000 feet had a conspicuous summer flora consisting of eriogonums, pentstemons, lupines, 

 evening primroses, painted cups, and golden-rods. A full list of the species is to be pub- 

 lished later. — W. N. Clute. 



322. Coville, F. V. The threatened extinction of the box huckleberry, Gaylussacia 

 brachycera. Science 50 : 30-34. July, 1919. — As the title indicates, the article is designed to call 

 attention to the fact that the Box Huckleberry is in danger of extinction; at the present time 

 the only localities in which the plant is known to exist are in Perry County, Pennsylvania, 



