l8 9!-] • Current Literature. 



3* 



descriptions, has been that of Michaux, supplemented by Nuttall, but 

 this was necessarily incomplete. In the great work 1 now undertaken 

 by Professor C. S. Sargent, the whole subject is to be presented in 12 

 quarto volumes, superbly printed and illustrated, the first of which has 

 now appeared. Professor Sargent's connection with the forest volume 

 of the 10th census is well known, and no one more competent could 

 have been selected to undertake the work. That the plates will be all 

 that can be desired is evidenced by the fact that the drawings are to 

 be made by C. E. Faxon and engraved by Philibert and Eugene 

 Picart. North American botanists are to be congratulated upon the 

 appearance of this great work, and while its price will put it beyond 

 many private purses, it should find its way into all public libraries, 

 and should be considered a part of the equipment of every botanical 

 department in our colleges. The definition of "trees" is a difficult 

 one, and the author very rationally proposes to follow habit rather 

 than size, a division which will include 422 species, besides numerous 

 varieties. In nomenclature the rule adopted is to use the oldest 

 generic name applied by Linnaeus in the first edition of the u Genera 

 Plantarum," published in 1737, or by any subsequent author, and the 

 oldest specific name used by Linnaeus in the first edition of the 

 44 Species Plantarum," published in 1753, or by an y subsequent author, 

 without regard to the fact that such a specific name may have been 

 associated at first with a generic name improperly employed. Thirty- 

 three species are included in this first volume. 



Plants as rock-makers. 



1 



Plants have long been known to play an important part in the ac- 

 cumulation of travertine, though we doubt whether sufficient credit 

 has been given to vegetation as a geological agent in this matter. In 

 an elaborate memoir 2 by Walter H. Weed, forming part of the ninth 

 annual report of the director of the U. S. Geological Survey, it is 

 shown not only that very large deposits of travertine are due to the 

 aid, direct and indirect, of vegetation, but also that the extensive de- 

 posits of siliceous sinter in the Yellowstone geyser region are in large 

 part due to the separation of the silica from the water by plants. 



1 Sargent, Charles Spragi ;k. — The Silva of North America, a description 

 of the trees that grow in N. Am. exclusive of Mexico, Vol. I. Magnoliaceae- 

 Ilicineae pp. ix. 119, 50 plates, large 4to, Boston and New York: Houghton 

 Mifflin & Co., 1891. — $25 per volume. 



2 Weed, Walter Harvey. — The formation of travertine and siliceous sinter 

 by the vegetation of hot springs, pp. 619-676, 9th Ann. Rep't, U. S. G. S. 

 figs. 5, pis. 10. Imperial 8vo. Washington: Government Printing Office, 

 1 890. 



