Floristik, Geographie, Systematik etc. 249 



island since the eruption. The results of the paper are summarized 

 as follows: 



The Vegetation of Volcano Island before the eruption of 1911 

 consisted of a mixture of grass and small trees, which covered all 

 parts of the island except the slopes of the main crater and Mount 

 Tabaro and the dry stream beds. 



The eruption of 1911 completely destroyed the Vegetation over 

 most parts of the island, while in the extreme northern part a few 

 bamboos, bananas, trees, and possibly some grass escaped. 



In the revegetation of the island a Single species of grass, 

 Saccharum spontaneum, is so much the most prominent of all the 

 invaders that it gives character to the whole Vegetation. Except in 

 the northern part of the island, it occurs as scattered clumps. 

 Besides Saccharum the other most conspicuous elements are scattered 

 trees. 



The revegetation is proceeding slowly owing, probably, to 

 adverse environmental conditions, the most prominent of which are 

 the presence of excessive arnounts of sulphates in the soil; the lack 

 of weathering of soil particles; the scarcity or absence of humus; 

 the scarcity of nitrogen; the low waterholding capacity of the soil; 

 and erosion. 



Two hundred ninety-two species of plants have been found on 

 Volcano Island since the eruption. These represent 232 genera and 

 66 families. 



Most of the species of plants on Volcano Island are those 

 of wide geographic distribution. Ninety-six, or 36 per cent, are found 

 in the tropics of both hemispheres, while an additional one hundred 

 fifty, or 51 per cent, are found in other parts of the Indo-Malayan 

 regions as well as in the Philippines. 



Very few of the species of plants on Volcano Island have 

 found favorable habitats over any considerable area, as only 13 are 

 common and widely distributed. 



Birds seem to have been the most important agency in bringing 

 different species to Volcano Island, as 54 per cent of the total on 

 the island could have been carried to it by this means. 



Jongmans. 



Brown, W. H. and H. S. Yatea. The rate ofgrowth ofsome 

 trees on the Gedeh, Java. (Philippine Journ. Sc. C. Bot. XII. 

 p. 305—311. 1917.) 



The writers made a number of measurements on Koorders' 

 labeled trees on the Gedeh. The rates of growth of these trees, in 

 the limited number of cases measured, would indicate that these 

 trees grow about as rapidly as the dominant trees in the Philip- 

 pines, Shorea robusta in India, and hardwoods in the central 

 hardwood regions of the United States. Jongmans. 



Butters, F. K., Taxonomic and geographic studies in 

 North American ferns. I. The genus Athyrium and the 

 North American ferns allied to A. Filix femina. II. Botry- 

 chium virginianum and its american varieties. (Contr. Grav 

 Herb. Harvard University. N. S. LI. Rhodora. XIX. p. 170-216. 

 PI. 123. 6 Textfig. 1917.) 



The first part of this paper, treating on Athyrium, is diride'd 



