4(30 SEDGE FAMILY. 



C. alternifoliuSi Linn. Umbrkm.a Pi.an-t. A grecnliouse aquatic from 

 Madagascar ; culms in clumps, 'l^-CP tall, smooth and triangular, leafless 

 below, but bearing a leafy, many-rayed, great involucre at the top, from 

 the axils of which sjiring slender-i)eduncled small clusters of flowers. 



C. Papyrus, J^inn. (I'APVitis a ntiqi <jrl' .■*!). E<;yj'tiax 1'ai'ek Plant. 

 Sometimes grown in aijuaria, not hardy N. ; sends up a jointless triangular 

 stem 4'^-10'^ high, which is terminated by a great involucre of very narrow 

 drooping or bending leaves. 



= = Bristles ahant the akene, n-ldrh is hodked on top. 



2. DULICHItJM. Spikclets G-10-flowered, sessile in 2 ranks on axil- 

 lary iifduuclLs springing from the sheaths of the leaves. Perianth com- 

 posed of (5-9 barbed bristles. 



One species, D. spathaceum, Pers., in bogs and on borders of pomls, 

 remarkable in the family for iuiving terete and hollow culms, l°-2" high. 



++ -w Scales not 2-ranke(l, the spikelet therefore terete. 



= Bristles ; culm lenfij. 



3. FIMBRISTYLIS. Spikelets umbelled, the involucral leaves 2-3. 

 ymall plants of either low or dry grounds, of about a half dozen species 

 in our territory. 



= == Bristles gencralhj jiresent ; culm leafy or naked. 



II Style someichat thickened or bulbous at the base, and pei-sistent %ipon the 

 top of the akene. 



4. ELEOCHARIS. Spike one, and without involucre, terminating a 

 .slender, simple, leafless culm. Many .species (mostly small) in moi-st 

 grounds and borders of ponds. 



II i! Style not swollen at the base, deciduous. 



5. SCIRPUS. Spikelets generally clustered in a compound umbel. 

 Bristles (sometimes 0) barbed. Mostly tall, rush-like, leafy, common 

 plants, but in some species the stems are slender and leafless, and the 

 spike is single and terminal, thus approaching Eleocharis, but the invo- 

 lucre is present in the form of a scale or small leaf. This genus now 

 includes Isoi.epis, to which the slender species with a .solitary terminal 

 spike, leafless and jointless culms, have been referred. 



6. ERIOPHORUM. Like Scirpus, but the bristles not barbed and 

 often becoming silky and long exserted in fruit. A few plants in bogs, 

 mostly distinguished when mature by the white, or rusty, woolly heads. 



•t- t- Spikelets only l-2-tfov:ered, and 2 or many of the lower scales Jlower- 

 less. 



7. RHYNCHOSPORA. Spikelets flattish, clustered, or panicled, 

 often whitisli or rusty in color. Bristles usually surrounding the 

 beaked or tubercle-topped akene. A score of critical species, mostly 

 small and slender plants, in bogs. 



8. CLADIUM. Spikelets terete. Akene not tubercled, and no bris- 

 tles. A single species, C. mariscoides, Torr., l'^-2^ high, in wet 

 places, with small, rusty cymes of capitate .spikelets. 



