168 CYPERACEAE 
I. CAESPITOSI 
Involucre wanting: annuals 
Lavoni e present, of a single bra 
Per pr E present: Scales nof keeled: perennial 
B p NN upper sheath with a subulate blade: 
perianth-bristles smooth or oM nwardly barbed. 
Achene about 1.5 mm. lon perianth-bristles 
smooth : apn cle slightly meee than thick: bog 
or rock plan 
Achene 2-3 mm long: perianth-bristles barbed : 
he several times longer than thick: aquatic 
or semiaquatic. 
Scape tria ular: u upper sheath with a linear blade: 
e 
II. VALIDI 
SE few, 1-12, appearing lateral. 
Scape not sharply 3-angled : plants annual. 
chene strongly transverse-rugose: perianth-bristles 
wanting. 
Ad smooth or very slightly roughened: perianth- 
Scape sharply 3-angled: plants pun Dy rootstocks. 
Spikelets acute: scales aw A : involueral bract much 
ce. 
only sli ence. 
Spikelets Berol or numerous, in umbels or umbel-like clusters. 
m bec 3-angled: leaves with blades about as long 
as the 
Scape terete: leaves reduced to mere sheaths. 
Perianth-bristles downwardly barbed : achene gray, or 
darker, abruptly mucronate. 
Perianth- bristles short- plumose below: achene nearly 
white, narrowed abov 
III. SYLVATICI 
Spikelets few to several, capitate to S Ioa relatively large, 
E Ad compound clusters: achene lobose-obovoid, dark- 
Spikelets very ee in compound umbels or umbelled 
heads, relatively small. 
Perianth-bristles « downw: ardly barbed, or wanting : spikelets 
Perianth-bristles present. 
Perianth-bristles a or tig exceeding the 
achene: leaf-blades 6-16 m wide. 
Spikelets 3-8 in ach head : ‘scales obtuse: peri- 
PEE 8-20 in each head: Seales acute: peri- 
Í istle 
th- 
Perianth- anes me as long as the achene: leaf- 
blades 4-6 m vide. 
Per ünth-bristies fastu 
Perianth- b. tles sm ond or slightly pubescent: umbel 
decompou 
Perianth-bristles shorter than the scales or scarcely ex- 
cee 
er TE briedes about as long as the achene : scales 
rather acute 
M merely terminal: spikelets 1 mm. 
thick : not papillose. 
thick: achene papillose. 
Perianth- h-bristles much longer than the achene: 
ales mucronate. 
Verianth. m much exserted beyond. the scales at 
Spikelets sessile, in small heads or clus ters 
EDU at least some of them, distinctly pedun- 
IV. CUBENSES 
Perennial herb, resembling species of Cyperus: leaves and 
bracts of the involucre quite similar. 
12. 
“10> 
8. 
19. 
20. 
23. S. 
n 
tata 
Nn 
NANUS. 
. caespitosus. | 
. subterminalis. 
. Clinto 
E IS: 
. Hallii. 
debilis. 
. americanas. 
Olneyi. 
. etuberculatus. 
. validus. 
. californicus. 
. robustus. 
sylvaticus. 
atrovirens. 
polyphyllus. 
georgianus. | 
. divaricatus. 
. fontinalis. 
. lineatus. 
. cyperinus. 
2 * S. 
| 
| 
| 
| 
| 
| 
| 
Eriophorum. 
cubensis. 
