96 Rhodora [May 
t2 Ne He 
onn 
13. 
13. 
14. 
ANALYTICAL KEY TO THE SPECIES. 
. Spikelets in one-sided, usually simple racemes . . . ‘ (di 
. Spikelets variously paniculate i : ` i $ A 
. Racemes slender, digitate or sub-fasciculate, outer r qtii pubescent. 3 
. Racemes thick and racemed along the main axis, outer glumes muricate- 
hispid . : . CERE 
Rachis of the racemes langues, the apes naked, not waned spikes 
very slender . . . 1. P. FILIFORME. 
. Rachis of the racemes flattened with the Lette angles broadly winged 4 
. Spikelets about 3 mm. long; second glume one-half as long as the spike- 
let i : a : : . 2. P. SANGUINALE 
. Spikelets atone 2 mm. ike: ond ghi about equaling the spike- 
let : . 3 P. HUMIFUSUM 
. Sheaths aiio ioweriug vivis ond aivapity pointed 
34. P. CRUS-GALLI 
. Sheaths hispid; flowering glume ovate-lanceolate, acuminate 
35. P. WALTERI 
. Leaves all alike, spikelets acute (77omogfAyl/a). . ` s : M 
. Leaves dissimilar, basal ones shorter and broader than those above; leaves 
of the branches usually much smaller and more crowded than those of 
the primary stem; spikelets abruptly acute or obtuse (P. depauperatum 
excepted) (7ZeferopAylla) . . : . . . . . ( 2 
. Spikelets 1.5 to 3 mm. long . . : : . “ A " ee 
. Spikelets 4 to 6 mm. long ] í . : ‘ è ‘ EET 
. Panicles ovoid or oblong; primary branches spreading or ascending; 
secondary branches appressed. Perennials 
. Panicles ovate, often as broad as long, their slender few- powered br sachin 
widely spreading. Annuals or perennials > . . IO 
. Culms stout, much branched; secondary branches of the juan Senile 
flowered; lateral panicles numerous; spikelets 1.5 mm. long, rather 
blunt; ligule naked . A k à 4. P. AGROSTOIDES 
. Culms slender, simple; secondary br sicul of the panicle few-flowered ; 
lateral panicles usually wanting or occasionally one; spikelets very 
acute, 2 mm. long; liguleciliate. . . . 5. P. LONGIFOLIUM 
. Sheaths glabrous . , : . . . : . ‘ j eae 
Sheaths papillose-pubescent . : i ; i ‘ ae 
. Outer glumes warty-roughened brer : 4: p. VERRUCOSUM 
. Outer glumes smooth; first glume broadly obtuse . 9. P. PROLIFERUM 
Culms stout, finally much branched throughout, spikelets very acute, 
2.5 mm. long, solitary . . . . . IO. P. CAPILLARE 
. Culms slender, branched ónly at the bini) spikelets rather blunt, 2 
mm. long or less, usually in pairs . : i . . II. P. MINIMUM 
Annual; sheaths hispid i a . . : . I2. P. MILIACEUM 
Perennial; sheaths glabrous . . . s , - 
Panicle very narrow, contracted ; spikelets 5 to 4 mm. long 
6. P. AMAROIDES 
