No. 40. 
TRIODIA TRINERVIGLUMIS (Munro) (Tricuspis trinerviglumis Munro 
in Herb.) 
Plant perennial, with slightly thickened tufted base. 
Culms erect or geniculate below, rarely branching, terete, hispid, 2 to 3 feet tall. 
Leaves; radical and of radical shoots numerous, with loose, pubescent sheaths 
and involute, hispid, often pubescent blades, 3 to 6 inches long; of culm 4 to 6; 
sheaths longer than internodes, open above, upper ones nearly smooth; blades like 
those of radical leaves; ligule an inconspicuous fringe. 
Inflorescence a narrow, erect, spike-like panicle, 4 to 8 inches long; branches 
erect, simple, almost appressed, $ to 2 inches long, or often reduced to single 
spikelets a little distant, or interrupted. 
Spikelets oblong or oblanceolate, but little compressed, 7- to 9-flowered, 3 to 5 
lines long; first glume lanceolate, obtuse or nearly acute, carinate, scarious, 7- 
nerved, 2 to 3 lines long; second glume lance-ovate, acute, carinate, scarious, sca- 
brid, hispid on keel, 3-nerved, 24 to 34 lines long; internode of rachilla stout, 
pubescent, articulate above, } line long; floral glumes oblong-ovate, obtuse, emar- 
ginate, mucronate or entire at apex, 3-nerved, pubescent below, lateral nerves 
vanishing before reaching the margin, palet ovate, obtuse, pubescent on the 2 keels, 
14 lines long. 
Grain ovate-conical, deeply hollow on one side, dark-brown, punctate, 1} lines 
long. 
Piate XL; a, spikelet; b, and b’, empty glumes; ¢, floral glume dorsal and 
side views; d, and e, palet, ventral and side views. 
Prevails throughout Texas, westward to Arizona, and northward to Colorado. 
Apparently not of great agriculturalimportance. Tricuspis mutica Torr. appears 
to be a smaller form, with shorter, interrupted panicle. 
