9 



Lasiopoa Ehrh. Beitr. 4 : 147. 1789. 



Ceratovhloa Beauv. Agrost. 75. /. 15. f. 7. 1812. 



ScJiedonoi-us Beauv. Agrost. 99. 1812. This, apparently by mistake, stands Sche- 

 nof7or((.9 in the index, 177, of the work cited. Beaiivois included under Schedono7-us 

 mostly s^jecies of Festuca. He cites no type for the genus, so we have accepted the 

 first species mentioned, Festuca elatior L., as the type. Only one or two species of 

 true Bromus were included by him, one of which was B. inermis. 



Zcrna Panz. Denkschr. Acad. Miinch. 296. 1813. 



Mkhelaria Dum. Obs. Gram. Belg. 77. /. 16. 1823. 



Libertia'Le]. Nov. Act. Nat. Cur. 12:755. i. 65. 1825. 



Serrafalcus Pari. PI. Nov. 75. 1842. 



Anlsaniha C. Koch, Linnsea 21 : 394. 1848. 



Triniu.'iia Steud. Syn. PI. Gram. 328. 1854. 



Bromopsis Fourr. Ann. Soc. Linn. Lyon n. ser. 17: 187. 1869. 



Zcrna was originally made to include the species of the subgenus Stenobromus as 

 well as those related to B. asper. 



Mkhelaria and Libert ia are synonyms, both being founded on B. arduennensis Dum., 

 a Belgian species resembling B. .<iquarrosus somewhat but having the angle on the 

 margin of the flowering glume extended in the form of a tooth. 



Serrafalcus was apjilied to the group containing B. secalinus and closely allied spe- 

 cies, which Linnseus regarded as typical of his genus BromU'S. 



Anisaiithii was founded on B. pontica Koch, which is considered to be B. tectorum'L. 



Bromopsis ^\•as applied to B. asper and B. erectus, and is synonymous with Zerna, as 

 here emended. 



Triniusia was founded on B. danthonise Trin., and maybe a valid genus. It is not 

 represented in our territory. 



The greatest difficulties in the treatment of the subject are connected 

 with the segregation and delimitation of species and varieties. In 

 order to arrive at a stable basis for the foundation and separation of 

 species, it is quite necessary that one should know exacth" what the 

 type of each species is. Various authors differ as to the limitation of 

 species, and it can scarcely be expected that there will be a unanimous 

 opinion as to these limitations, but if the typical form of a species be 

 recognized and taken as the fixed point that must remain undisturbed, 

 however many or few forms may be grouped around it, much con- 

 fusion would be avoided. As a basis of the present revision we have 

 made a careful study of the original descriptions of the species and 

 also have had an opportunity of examining the types or portions of 

 the types of the most of our endemic forms. This has shown the 

 necessity of a number of changes in the nomenclature of our species, 

 the determination of some of them having heretofore rested upon 

 traditions and interpretations, which investigations of the types prove 

 to be incorrect. Besides the study of original descriptions and types, 

 we have had an opportunity to study most of the forms in the field 

 during the past five seasons, and have also been able to examine the 

 collections of a number of the larger herbaria of this country. The 

 species, as in most of our genera of wide distribution, are very varia- 



