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1907] CURRENT LITERATURE 231 



of twelve years at the University of Strassburg, and was prepared for the press at 

 the solicitation of friends. 



The author enters a disclaimer as to any originality except in the selection of 

 the material and its presentation. His purpose is quite other than that of Grise- 

 BACH, Drude, and Schimper, who have sought to present the facts of plant dis- 

 tribution in a comprehensive way. Solms-Laxjbach discusses several large topics, 

 whose enumeration sufficiently indicates the scope of his work: species and their 

 alteration in time; the habitat; the occupation of habitats by species; the dis- 

 turbance of the equilibrium of distribution by external causes; island floras. In 

 discussing these topics he cites illustrative examples, but omits pictures and lists 

 of vegetation. A historical introduction and a brief recapitulation of the most 



general principles of geographic distribution form a suitable preface to the special 

 topics. , 



Under the topic ''the species" we find a discussion of the origin both of the 

 concept and the corresponding plant groups, in which the concepts of Linnaeus 

 and Jordan and the theories of Lamarck, Darwin, Nageli, and DeVries are 

 set forth. The topic ''habitat" includes a discussion of the relations of external 

 factors to plant form — -"adaptations" in the broadest sense. The means and 

 methods of distribution, which make it possible for plants to occupy a habitat, are 

 described briefly. Alterations in the habitat by invasion of plants, and especially 

 secular alterations of climate, such as that involved in the last glacial period, with 

 the consequent migrations, are discussed at some length. The insular floras, as 

 conditioned by the hindrances to plant distribution, are characterized briefly. 



As a book for reading in connection with the more systematic works, these 

 lectures will be found serviceable as well as inteiresting. — C. R. B. 



MINOR NOTICES 



Contributions from the Gray Herbarium. — The current number of this scries^ 

 contains four parts: I. "New species of Senecio and Schoenocaulon from Mexico," 

 by J. M. GREENM.A.N, 3 new species of the former genus and 2 of the latter being 

 described. IT. "New or otherwise noteworthy 



spcrma 



Mexico," by B. L. Robinson, new species being described under Tigridia, Schocp- 

 fia, ]Mimosa, Pedilanthus, Bonplandia, Brittonastrum (3), Russelia, Stemodia, 

 Piqueria, Stevia (2), Eupatorium (10), Brickellia, Guardiola, Zinnia, Per)Tnen- 

 ium. Coreopsis, Tridax, Pericome, Tagetes, Cacalia (3), Perezia (2); and two 

 new genera of Compositae, Cymophora (Helianthieae) and Loxoihysanus (Helen- 

 . ieae). III. "New plants from Guatemala and Mexico, collected chiefly by 



C. C. Deam," by B. L. Robinson and H. H. Bartlett, new species being de- 

 scribed under Polypodium, Paspalum, Fuirena, Myriocarpa, Polygonum, Ruprech- 

 tia, Aeschynomene, Mimosa, Tetrapteris, Euphorbia, Acalypha, Clus.ia, Rinorea, 



5 Contributions from the Gray Herbarium of Harvard University, N. S. 34. Proc. 

 Amer. Acad. 43:19-68. 1907, 



