GUAMINE^. (grass FAMILY.) 553 



^ 1. CHONDROSIUM, Desv. — Spikes pectinate, of very mam/ spiketets, oblong 

 or linear, very dense, solitari/ and terminal or few in a raceme : sterile flowers 1-3 

 on the summit of a short pedicel, neutral, consisting of 1-3 scales and awns. 



1. B. Oligostuchya, Torr. Glabrous, perennial (6' -12' high) ; leaves 

 very narrow ; spikes 1-5, the rhachis glabrous ; glumes and lower fertile palea 

 sparingly soft-hairy ; the lobes awl-pointed ; sterile flower copiously villous-tufled at 

 the summit of the naked pedicel, the 3 awns equalling the larger glume. 

 (Atheropogon, Nutt.) — W. Wisconsin? and westward. — Glumes obscurely 

 if at all papillose along the keel. Middle lobe of the lower palea 2-cleft at the 

 tip. Sterile flowers often 2, the second mostly a large awnless scale, becoming 

 hood-like and coriaceous. (Near B. gracilis : perhaps B. juncifolia, Lag.) 



2. B. hirsuta, Lagasea. Tufted from an annual? root (8'- 20' high); 

 leaves fiat, lance-linear, papillose-haiiy or glabrous ; spikes 1 - 4 j lower glume 

 hispid with strong bristles from dark warty glands ; lower palea pubescent, 3-eleft 

 into awl-pointed lobes ; sterile flower and its pedicel glabrous, the 3 awns longer than 

 the glum.es and fertile flower. (Atheropogon papillosus, Erujclm. Chondrosium 

 hirtum, H. B. K.) — Sandy plains, Wisconsin, Illinois, and sonthwestward. 



§ 2. ATHEROPOGON, Muhl. — Spikes short, numerous in a hng and virgaie 

 one-sided spike or raceme, spreading or reflexed, each of feu) (4-12) spikelets: 

 sterile flowers neutral, rudimentary. 



3. B. curtipcndula. Culms tufted from perennial rootstalks (l°-3° 

 high) ; sheaths often hairy ; leaves narrow ; spikes J' or less in length, nearly 

 sessile, 30 to CO in number in a loose general spike (8'- 15' long) ; flowers 

 scabrous ; the lower palea of the fertile with 3 short awl-pointed teeth ; sterile 

 flower reduced to a single small awn, or mostly to 3 awns shorter than the fertile 

 flower, and 1 or 2 small or minute scales. (B. racemosa, Lagasea. Cliloris 

 curtipcndula, Michx. Atheropogon apludioides, Muhl. Entriana curtipcndula, 

 7rin.) — Calcareous dry hills and plains, S. New York to Wisconsin, and south- 

 ward. July - Sept. — Passes by transitions into 



Var. ai'istosa. Spikes mostly shorter ; sterile flower of a large saccate 

 lower palea, awned at the 2-cleft tip and from the lateral nerves, the stout mid- 

 dle awn often exserted, and sometimes with a rudiment of an inner palea. 

 (Eatriana alEnis, J. D. Hook.) — Illinois {Geyer), Penn. ? and southward. 



19. GYMIVOPOGOW, Beauv. Naked-beaed Gkass. 



Spikelets of one peifect flower, and the rudiment of a second (consisting of 

 an awn-like pedicel mostly bearing a naked bristle), sessile and remotely alter- 

 nate on long and filifonn rays or spikes, which foi-m a crowded naked raceme. 

 Glumes lance-awl-shaped, keeled, almost equal, rather longer than the somewhat 

 equal membranaceous paleas ; of which the lower is cylindrical-involute, with 

 the midrib pi'oduced from just below the 2-cleft apex into a straight and slender 

 bristle-like awn ! the upper with the abortive rudiment at its base. Stamens 3. 

 Stigmas pencil-form, purple. — Leaves short and flat, thickish, l'-3' long. 

 (Name composed of yvfivos, naked, and Tnayiai/, a beard, alluding to the reduc- 

 tion of the abortive flower to a bare awn.) 

 47 



