112 REVIEWS. 



It is in this way that Mr. Vihnorin supposes cross-fertiliza- 

 tion to operate in the production of new varieties ; and even 

 in the crossing of two distinct species, the result, he thinks, is 

 rarely, if ever, the production of a fertile hybrid, but of an 

 offspring which, thus powerfully imjjressed by the strange 

 fertilization and rendered productive by the pollen of its own 

 female parent, is then most likely to give origin to a new race. 



We cannot follow out this interesting but rather recondite 

 subject in a brief article like this. But we are naturally led 

 to inquire whether the history of those plants with which man 

 has had most to do, and the study of the laws which regulate 

 the production and perpetuation of domesticated races, may 

 not throw some light upon the production of varieties in Na- 

 ture ; and whether races may not have naturally originated, 

 occasionally, under circumstances equivalent to artificial selec- 

 tion and segregation. Some recent attempts which have been 

 made in this direction we may hope to notice upon another 

 occasion. 



THE BUFFALO-GRASS. 



The Buffalo-Grass,^ so abundant and so widely diffused 

 over the broad, arid region which separates our Pacific from 

 our Atlantic possessions, is one of the humblest plants of its 

 order, rising only a few inches above the surface of the soil ; 

 but at the same time it is one of the most important and use- 

 ful, since it forms the principal subsistence of the buffalo for 

 a part of the year, and no less so of the cattle of the emigrant. 

 The botanical history of this little grass, now happily com- 

 pleted by Dr. Engelmann, is remarkable. Nuttall first named 

 and described it nearly thirty years ago ; and, while he re- 

 ferred it to Sesleria, suspected it to be sui generis, and threw 



^ Two new Genera of Dicecious Grasses of the United States. By George 

 Engelmann, M. D. Extr. from the Transactions of the Academy of Nat- 

 ural Sciences of St. Louis, i. p. 431 ; with three plates. 1859. (American 

 Journal of Science and Arts, 2 scr., xxviii. 439.) 



