MR. G. BENTHAM OS GUA.UIHEX. 97 



straight awns, one on each side of the dorsal twisted one, and in 

 the grain glabrous or slightly pubescent at the apex without the 

 longitudinal furrow of Avena. The inflorescence is also usually 

 more dense than in that genus, with smaller, often shining spike- 

 lets. A few African or South-American species, however, such 

 as T. hirtum, Nees, and T. antarcticum, Nees (whicb includes 

 Bronius antarcticus. Hook, f., and Bromus hicuspis, Nees), closely 

 connect the two genera : the flowering glume is more rigid and 

 less keeled than in the true Triseta, and the ovary is pubescent 

 at the top ;but the grain has not the furrow of Avena. Triehata, 

 Beauv., is the Trisetum ovatum, Pers., a species allied to T. sub- 

 spicattim ; but the spikelike panicle is more dense and ovoid, or 

 almost globular. Acrospelion or Aeropselion, Bess., is Trisetmn 

 distichophi/llum, Beauv., not the Ventenata, Link, to which it is 

 referred in Lindley's ' Vegetable Kingdom.' Mostraria, Trin., 

 was made up of Trisetum neglectum, Eoem. et Schult., and Koeleria 

 phJeoides, Pers. 



8. Ventenata, Keel., has two species, V. avenaeea, Koel., and 

 Y. macra, Balansa, from the Mediterranean region and Central 

 Europe, differing slightly from Trisetum in the longer, more rigid, 

 many-nerved glumes, and the absence of any dorsal awn on the 

 lower flowering one. 



9. Atena, Linn., as limited by recent authors, comprises about 

 forty species, mostly from the temperate regions of the Old 

 World, with a few from extratropical North and South America, 

 and one or two of the annual ones cornfield weeds in other coun- 

 tries. It is generally characterized by the flowering glumes 

 rounded on the back and several-nerved, with a dorsal twisted or 

 bent awn, and by the ripe grain furrowed in front and more or 

 less adhering to the palea, but is divisible into two sections almost 

 marked enough in habit as well as character to be raised to the 

 rank of genera. In 1. Crithe, Griseb.,the species are all annual, 

 usually tall, with a loose panicle of large pendulous spikelets, each 

 containing no more than two fertile flowers, and often only a 

 single one, and the lower empty glumes 7- or 9-nerved. This 

 section includes the common Oat, which has lost its dorsal a^yn 

 probably as a consequence of long cultivation; for the plant is 

 unknown in a wild state, except here and there as an escape 

 from cultivation. In 2. Avenastrum, Koch {Helicotriohum, Bess.), 

 the plant is perennial, the panicle usually narrow, with erect or 

 rarely spreading spikelets with more than two perfect flowers, 



