AVENE^. 375 



Mexico, rvingh 3950. 



4. T. filifolium Seribu. iued. 



A densely tufted perennial, about 60 cm. high. Culms few, 

 simple, erect. Leaves of sterile shoots numerous, scabrous, glau- 

 cous, involute, filiform, 8-12 cm. long, 0.5 mm. broad. Sheaths 

 of the culm 2, much shorter than the internodes, the ujiper reacli- 

 iug to the middle of the culm; ligule 1 mm. long; blades filiform, 

 5-8 cm. long. Panicle rather dense, contracted, lanceolate, 7-10 

 cm. long, the lowest rays in half-whorls of 4-8, the longest 4-5 cm. 

 long, flower-bearing beyond the middle. Spikelets subsessile or the 

 terminal ones on short pedicels, linear, 2-3-flowered; empty glumes 

 acute, 1-nerved, first linear-lanceolate, 3.5 mm. long, second oval- 

 lanceolate, 3.7-4 mm. long, the hairy joint of rachilla 1.2 mm. long; 

 floral glume obscurely keeled below, lateral nerves obscurely 2- 

 nerved, scabrous, oval, 3-3.5 mm. long, truncate, 2-lobed, with a 

 very short straight awn in the notch ; palea linear before spreading, 



3 mm. long, with two scabrous keels. 



Mexico (Chihuahua), Pringle 1431. 



Cool slopes of the Sierra Madre, at the altitude of 9000 feet. 



Var, aristatum Scribn. ined. 



Leaves of sterile shoots 30-40 cm. long; panicle thin, narrow, 

 12-20 cm. long, half- whorls of rays 3.5-4.5 mm. distant, the long- 

 est filiform ray 4-6 cm. long. Spikelets tipped, pedicellate; empty 

 glumes with a bristle 0.5 mm. long; floral glume thin, keeled, oval, 



4 mm. long, obscurely 5-nerved, the apex with 1-2 bristling teeth 

 on each lobe extending one-third the way down, awn in the notch 

 twisted and reaching three-fourths of 1 mm. beyond the apex of 

 its glume. A very marked variety at least, perhaps a species. 



]Mexico, Pringle 1430, on cool slopes of the Sierra Madre, at an 

 altitude of 9000 feet. 



5. T. HaUii Scribn. Bull. Torr. Club, 11: G (1884). 



Culms smooth, slender, 15-45 cm. high. Leaf-blades flat, invo- 

 lute near the apex, these of the culm 2-7 cm. long, 1-2 mm. wide, 

 minutely scabrous. Panicle contracted, 5-10 cm. long, the erect 

 densely flowered rays 2 or more cm. long. Spikelets 2-3-flowered. 

 rachilla nearly smooth, prolonged above the upper floret, often 



