POACEAE * o0 
indurate, the margins inrolled.—Over 300 species, widely distributed in the 
warmer parts of both hemispheres. | 
Rachis with broad green membranous wings. (Subgenus CERESIA.) ™ I. DISSECTA. 
Rachis not winged or very narrowly so. 
Racemes in pairs at the summit of the stem, rarely a third 
one’ below, divaricate at o spikelets solitary. . 
Spikelets narrowly ovate, 3-4.5 mm. long. II. DISTICHA. 
Spikelets ee circular, 1.5 mm. “Tong. III. CONJUGATA. 
Racemes Ra -many, racemose on the axis, not in pairs at the 
mmit. 
Fruit A ale. 
Spikelets not over 2 mm. long (except in no. 6) : slen- 
der leafless flowering branches borne in the upper 
she aths (except in nos. 7-10). V. SETACEA. 
Spikelets over 2 mm. long: branches, if any, le afy. 
First glume usua ally present on one of each pair of 
Spikelets, Du. ee on both: plants producing ; 
scaly rhizo V. BIFIDA. 
First glume uni ng. 
Spikelets glabrous : leaf-blades flat or folded, 
-12 mm VI. LAEVIA. 
Spikelets with " ‘Silky fringe around the margin, 
in pairs VII. DILATATA. 
Fruit dark brown at maturity VIII. PLICATULA. 
CI. Dis 
Racemes not more than 6, usually x or 4: ee broadly A rachis not extend- 
ing beyond the uppermost Spikelet P. dissectum. 
Racemes numerous : spikelets about half as broad as long: 
rachis extending as a point beyond the spikelet. 2. P.repens. 
II. DisTICHA 
Sterile lemma wrinkled in the internerves: spikelets 
glabrous, flattene 9. P. vaginatum. 
Sterile lemma not wrinkled : second glume pubescent. 4. P. distichum. 
III. CoNJUGATA 
Plant stoloniferous ; widely creeping. 9. P. conjugatum. 
IV. SETACEA 
First glume present in at least one of each pair of sid 
iu n obovate, appressed-pubescent, 2-2.5 mm 
r more long. 6. P. Langei. 
First glume wanting: spikelets not over 2 
Racemes 3-9, scarcely longer than the Corresponding 
alend. of the axis: leaf-sheath with an erect 
pointed auricle on each side at the sum 
axillary racemes rarely Dicen 
Spikelets about 1.3 mm. long, obovate, blunt, 
crowded, glandular- pubescen us T. P. Blodgettit. 
ur RET 1.5-2 mm. long, ellipt 
2-3 cm. long, ium thick 8. P. uo qun 
Racem Hes x Rp em. oe slender 9. P. lax 
Racemes 1 or 2, rarely 3, 2 or 3 times 19 onger than the 
axis internodes : leaf. Sheaths not auricled 
due rem So in P. ciliatifolium) : stems slen- 
Spikelets not over 1.8 mm. lon ng (if as much as 
1.8 mm., leaf-blades either’ pubescent 
on the surface or clustered at the 
bas 10. P. longepedunculatum. 
Spikelets 1.6-1.8 mm. long, oval: leaf- 
bla a ronin a villous, usually 
11. P. debile. 
Spikelets bau tib5m m. long, orbicular: 
eaf-bl es short pilose, usually not 
pen 4m wide. 2. P. setaceum. 
Spikelets 2 mm. longl or less in P. AE 
no ic Ey rarely over 4 mm. wid 
13. P. rigidifolium. 
Leaf-blades lanceolate to linear, K n lat- 
ter pubescent on both sur fac 
