160 | CYPERACEAE 
ecd terete 2 at least above: bristles smooth: tubercle 
f the achene deltoid. 
Seane angled or ened: bristles toothed: tubercle of 
the achene narrow lanceolate or shen 
Scape ate mostly over n diameter: tubercle 
e achene lanceolate. — 
Scape uere mostly less than 2 mm. in diameter: 
tubercle of the achene subulate. 
Achen e 2 2.5 mm. long, mostly lenticular : bristles 
abo uw equalling the top of the tuber 
Achene about 1 mm. long, mostly 3- 2d: bristles 
about equalling the base of the tubercle. 
II. OBTUSAE 
Upper sheath scarious, edm: plant perennial by slender 
rootstocks. 
Achene about 0.5 mm. lo ong. 
Se Te ab green or De white: perianth-bristles 
r than the achen 
Scales bonn pe bristles shorter than the achene. 
Bue about 1 m lo ons perianth-bristles longer than 
achene ; Beales: bro 
Upper cheat truncate, oblique. or toothed, not scarious. 
Plant annual, wit "fibrous roots 
Scape capillary : spikelets with 1-4 achenes. 
Scape slender: spikelets with several to many achenes. 
Achene black. 
COH about 0.5 mm. long: perianth-bristles 
usually 2-4, pues e mostly 2-9 cm. tall. 
Achene about 1 long: perianth-bristles 
m 5-8, Boost scape mos 5 
tall. 
Achene pale-brown to white. 
Scape filiform or bristle- like: achene white. 
Scales of the s a ikelets pale, with brown mid- 
rib: achene whitish: upper leaf-sheath 
Aire M obt iure 
Scales of the Bd dark, with whitish mid- 
rib and m argin S on either side of the dark- 
BEY. PD achene brown: upper leaf- 
Shcath sien eats, acute. 
Scape slender: achenes pale-brown. 
Perianth- no longer than the achene: 
spikelets ovoid. 
P bristies m. longer than the achene, 
ort or wanting: spikelets cylindric. 
Plant — I Wir DOr eont rootstocks. 
Sc as eg septate: achene about 1 mm. long: tuber- 
cle 
Scape ee achene 1.5 mm. long or nearly so: 
tubercle con 
III. TENUES 
Achene cancellate. 
Achene longitudinall d. 
Achene not itudinally miol ribbed. 
Scape filiform : spikelets with 1-4 achen 
Scape slender: spikelets with eee Samy, achenes. 
Ss linear- pt E often proliferous. 
Spikelets ovoid to conic-ovoid, not proliferous. 
Tu bercle conic. poene than the achene. 
ees miter-like, as large as the achene or 
Achene smooth, papi illose, or eee ridged-reticulate, 
dpud terete or nearly so, 6-20-flow 
Ac smooth, ellipsoi id-obovoid bus aS 
EO capillary : achene-body ia nr. P 
Scape filiform: achene-body long. 
Upper leat sheath] badeless: : perianth- -bristles 
oe ut as the achene: ache 
è tha 0.5 ae long, up D mm. 
Spikelet scales Jax, not coneealing the 
enes: perianth-bristles about as 
lone as the achene: achene ellipsoid- 
obovoid, nearly 1 mm. long, pale 
brown, the tubercle minute, depressed- 
. E. cellulosa. 
. E. quadrangulata. 
4. E. Robbinsii. 
. E. elongata. 
RA 
o 
. E. flaccida. 
. E. praticola. 
. E. olivacea. 
. E. capillacea. 
. E. atropurpurea. 
. E.caribaea. 
12. E. uncialis. 
.. E. bicolor. 
14. E. obtusa. 
. E. Engelmannii. 
. E. nodulosa. 
. E. calva. 
. E. acicularis. 
. E. retrofieza. 
. E. vivipara. 
. E. simpler. 
. E. tuberculosa. 
. E. microcarpa. 
. E. Torregana. 
