Cyperus. | CYPERACEAE. 461 
1. CYPERUS, L. 
Spikelets many- to few-flowered, laterally Rader rarely terete, in 
clusters or spikes, rarely solitary, the clusters or spikes sessile or on the 
sheathed rays of a simple or compound seve ate umbel. Glumes 
distichous (2-ranked), their decurrent bases often forming margins or 
wings to the Evins of the axis next below, the one or two lowest 
mpty. owers hermaphrodite, without hypogynous scales or bristles. 
Stamens 3 or fewer. Style not bulbous at the base, 3- or 2-cleft, deciduous. 
Achene triangular or hide! often one with the base of the style. 
— Stems simple, triangular, leafy at the base and with one or more leaves 
at the summit which form the involucre. 
A large bios and subtropical genus, represented by a few species in the more 
temperate re 
The iia bel or the involucral leaves really corresponds to that of the rays of the 
umbel, but they are of very unequal length, and those pertaining to short sessile spikes 
Tre qui i i i i , Which is most 
lowest glume 
others), the ochrea as closed sheath . longer radioles or branches, or as inner soon deci- 
duous bract in n shorter ones, and as second empty glume (or vorblatt) in the spikelet. 
The latter is tev shorter ‘than oo upper fertile glumes, more obtuse, and generall 
arweed at the 
n the lowest spikelets both. are present, but in the upper ones the outer or lowest 
are r es 
5 
the 
empty glumes, and these remain on ray after the lapse of the spikelet; in others, 
meme » With a continuous rhachis (C. cetadaaiomd: ri iralgiiaiiaes they are the first 
0 fa of 
In the following descriptions the number of involucral leaves given refers to those 
only edhe are conspicuous on first sight. In the number of glumes the two lowest 
em gs nes are always included. 
Style 
Nuts cae mpressed; spikelets in a dense cluster (Junceltus) 1. C. laevigatus. 
Nuts Salenatiy. compressed, geen Ne in a fascicle or umb 
(Pycreus) 2. C. polystachyus. 
Style 3-fid 
Fertile glumes 4 or more iRueiperne)s i 
Spikelets more or less compress 
Spikelets reddish, linear, spicate on the raysofasimpleumbel 3. C. rotundus. 
Spikelets pale brown or rust-colo’ 
Spikelets crowded in dense heads at the apex of the rays 
or of umbellate raylets, each with 12—30 scabrous glumes 7. C@. trachysanthus. 
a — on the rays of a simple or the alternate 
on of a compound umbel, each with 6—12 smooth 
Umbel ¢ shatk. nga hen rays less than 
Spikelets ova ressed, acute; rays cae umbel 
mete peaks Ain 4. C. pennatus. 
Spik rather tu id, _obtnse pays “mostly 
St cae ch rt 5. C. Hillebrandi. 
simple, or their branches very 
mbel large, open, twice or thrice compound spikelets 
turgid 
mete oblong, 6. C. caricifolius. 
