1^96. SOME NEW BOOKS. 275 



sized flora. In his preface the author discusses the geological history 

 of the island before proceeding to his remarks on its climate and 

 vegetation. The climate is largely determined by the direction of 

 the wind, the mountain chain which follows the longer axis of the 

 island sheltering one side from the S.E. wind, and inducing a dryness 

 which is only interrupted by rains brought by the N.W. cyclone. 

 These differences in climate are reflected in the vegetation. In the 

 south-east it is luxuriant, a bright green carpet covering the ground, 

 which is abundantly watered. The alluvial soil on the coast is exten- 

 sively cultivated with sugar-cane, maize, manioc, vanilla, tropical fruits, 

 and spices ; and screw-pines, bamboos, and palms abound. In the 

 north-west and west, on the contrary, the littoral zone is dry and indi- 

 genous species are rare, but the date-palm and other introduced plants 

 will thrive. At a certain altitude, however, the soil is remarkably 

 fertile and plant-life vigorous, thanks to the abundant dews. The 

 damp forests, their trees draped with mosses, ferns, and orchids, charac- 

 teristic of the soil on the S.E., are absent. x\s regards the island as a 

 whole, it has, in the writer's opinion, owing to its general outline, 

 differences in altitude, and climate, one of the most varied and 

 interesting floras which could be studied. Commerson seems to 

 have been the first to explore Bourbon botanically. He acted as 

 naturalist to Bougainville's expedition round the world, and after- 

 wards spent five years in Madagascar, Bourbon, and Mauritius, 

 where he died in 1773- He collected a large number of plants and left 

 many notes and sketches. Other well-known botanists who have 

 studied the flora of the island were Du Petit Thouars, Bory de St. 

 Vincent, Gaudichaud, Perrotet, and Boivin. More recently, Charles 

 Frappier, whom Mr. Cordemoy describes as a close and intelligent 

 observer, devoted during thirty years (1853-1883) a large amount of 

 time to the plants of certain districts. Orchids were his special 

 study, and he had undertaken to prepare this order for the flora, but 

 the work was unfortunately interrupted by his death. 



Mr. Cordemoy enumerates 1,155 species of flowering plants 

 which are indigenous to or naturalised in the island ; there are also 

 221 ferns and fern-allies, 360 mosses and liverworts, 128 lichens, 

 and 83 algae. The Fungi have not been worked up. A fair sprink- 

 ling of the species are here described for the first time. The useful- 

 ness of the descriptions would be greater if some diagnosis had been 

 included ; in many cases they occupy a whole page, through which 

 the reader must search for charaicters of importance. In the part 

 relating to the grasses, the work of Mr. C. J. de Cordemoy, the 

 opposite extreme is reached, for the descriptions of new species are 

 often from their brevity quite useless for purposes of comparison. 



Plants of North America. 



Synoptical Flora of North America. By Asa Gray, LT..D., and Sereno 

 Watson, Ph.D., continued and edited by B. L. Robinson, Ph.D. Vol. i., part i., 

 fascicle i. Imp. 8vo. Pp. ix., 208. Oct. 10, 1895. Harvard Univ. Price iis. 



" The aim of this comprehensive work is to give a critical treatment 

 of the Flowering Plants of North America, with concise but clear 

 descriptions, synonymy, bibliography, and geographic range of all 

 species and varieties, growing without cultivation on this continent, 

 north of Mexico ; also, ordinal, generic, and specific keys to facili- 

 tate the identification of plants included. 



" Of this extended treatise Dr. Asa Gray published, in 1878 and 

 1884, two parts including all the Gamopetalous Orders. These 

 parts (re-issued in 1886 by the Smithsonian Institution, Miscel. Coll., 



