1906] Lamson-Scribner,— Trisetum and Graphephorum 83 



emphasize the fact already noted, tliat the element of opinion or judg- 

 ment plays no small part in the deductions of the keenest observers. 

 That Beauvois was an acute observer of rare judgment his work 

 amply shows, and his diagnosis of Triseinm, here quoted, presents all 

 the essential characters embodied in the more pretentious efforts of 

 recent authors. "Axis paniculatus: Panicula composita.— Glumae 

 membranaceae, 3-5-florae, longitudine flosculorum: Palea infer, hiseia, 

 dorso supra medium arifitata: Arista herbarea, flexuosa, raro plicaia." 

 He separates D ant honia and Arena from Triseinm by the character of 

 the awn, which in these genera he describes as being plicate and twisted, 

 while Deschampsia has the apex of the flowering glume multidentate, 

 with the slender awn inserted near its base. He makes no mention 

 of the relationship of the genus with Eatonia, Koeleria, or Deyeuxia, 

 and fails to recognize the genus Venfcnafa, published by Koeler (Desc. 

 Gram. 272, 1802). 



Beauvois separates Graphcphornm chiefly by the shortness of the 

 awn: "paleae bifido-dentatae: infer, inter dentes mucronata." Hairi- 

 ness of the rachilla is common to most species of Trisetum, and there 

 are both North and South American species in which the awns are very 

 short or even suppressed entirely. Desvaux (Gay, Flor. Chil. 6: 352, 

 1853) forms a section in the genus, Sect. Koeleria, to include the 

 species in which the awns are straight, usually short, or sometimes 

 wanting. He includes in this section Trisetnm micratherum and T. 

 suharistatum. Grisebach (In Abhandl. Gesellsch. Wiss. Goett. 24: 

 292, 1879) transfers T. mirrathernm Desv. to Koeleria. I have seen 

 the grass referred by Philippi (Ann. Univ. Chil. 43: 568, 1873) to this 

 species, and would retain it in Trisetnm. It is distinguished from 

 Koeleria by its decidedly unequal empty glumes, bearded callus and 

 rachilla, and short subterminal awns. The texture and character of 

 the glumes are like those of T. Wolfii Vasey, and the inflorescence is 

 much the same as in that sj)ecies. Philippi (Ann. Univ. Chil. 94: 

 26, 1896) refers his Tri.setnin minniiflonnn to the same section — 

 (Koeleriae), but this grass is not referable to Tri.setum. It belongs 

 to the section Lophocliloa of Koeleria, being most closely allied to 

 K. phleoides and K. villosa Pers. 



Trinius (Fund. Agros. 157, 1820.) unites Trisetnm with Ar^ena, but 

 later (Mem. Acad. St. Petersb. VI, 1: 59, 1830) he takes up the genus 

 and in his diagnosis describes the flowering glume as "bidentate vel 

 bisubulate, dorso arista vel infra apicem setigera (rarissime mutica)." 



