166 NORTH AMERICAN FLORA {VoLumME 17 
A. Spikelets glabrous, or if pubescent the hairs shorter or not much longer than the spikelet, not 
auriculate at the base, the outer scales firm and usually with a midnerve, 
Spikelets with none of the scales winged. 
Fruiting scale with several longitudinal ridges. I, ELONGATA. 
Fruiting scale with no ridges. 
Racemes l-many, never conjugate at the summit of the stem. 
Stems erect and tufted, or prostrate and rooting at the 
lower nodes; stolons, when present, appressed, hence 
no long rootstocks, 
Rachis-wings broad, membranous, inrolled on the spike- 
lets. 
Wings colored, or if green reticulate ; spikelets long- : 
hairy. II. STELLATA. 
Wings green; spikelets not long-hairy. III. Dissecta. 
Rachis-wings narrow, not membranous nor inrolled on 
the spikelets, sometimes wanting. 
Spikelets of 4 scales. V. PEDUNCULATA. 
Spikelets of 2 scales. VI. PULCHELLA. 
Spikelets of 3 scales. 
Stems with leafless flower-bearing branches from 
the upper axils. 
Fruiting scale smooth and shining, or some- 
times minutely roughened. 
Spikelets broadly oval to obovate ; racemes 
usually 1 or 2, rarely more. IV. SETACEA. 
Spikelets elliptic, about one half as broad 
as long, or if broader then glandular- 
pubescent and racemes several. 
Spikelets glabrous or appressed-pubes- 
cent. XIV. CAESPITOSA. 
Spikelets glandular-pubescent. XV. LENTIGINOSA. 
Fruiting scale dull, manifestly roughened with 
papillae striately arranged. V. PEDUNCULATA. 
Stems without such branches. 
Outer scales of the spikelet normally with a 
midnerve; stems erect, or prostrate and 
rooting at the lower nodes. 
Fruiting scale broadly obtuse or rounded at 
the apex, sometimes apiculate. 
Rachis of the racemes without wings. XI. PORTORICENSIA. 
Rachis with wings. 
Spikelets glabrous, or with short 
pubescence, obtuse or merely 
acutish. 
Racenes few, less than 10. 
Fruiting scale white, yellowish, 
or greenish. 
Spikelets normally singly 
disposed. 
Spikelets elliptic, oblong, 
or ovate, not more 
than one half as broad 
as long, or if broader 
then less than 2 mm. 
long. 
Outer scales of spike- 
let, at least the first, 
3-5 nerved. VII FILIFORMIA. 
Outer scales 2-nerved, VIII. PaRVIFLORA. 
Spikelets broadly oval or 
orbicular, more than one 
half as broad as long, 2 
mm, long or more. IX. LaEvia. 
Spikelets normally in pairs. 
Cauline leaf-blades deeply 
cordate-clasping above. XIII. MICROSTACHYA. 
Cauline leaf-blades not 
cordate-clasping. 
Fruiting scale mani- 
festly papillose or 
warty. 
Spikelets 1.5 mm. 
long or less. 
Raceme single; 
spikelets more 
than 1 mm. 
long. XXXVI. NotatTa. 
Racemes 2-4; 
spikelets less 
than 1 mm. 
