Naias.] NAIADACEjfi. 439 



1. N. flex'ilis, Rostkov. ; leaves very slender, subentire. 



Lakes, Perthshire, Skye, and Connemara; fl. Aug.-Sept. — Stem filiform, 

 branched, brittle. Leaves §-1 in., opposite or 3 in a whorl, linear, quite 

 entire or remotely serrulate ; sheaths ciliate. Flowers 2-3 or solitary. Drupe 

 § in. — Distrib. Europe, Asia, America. 



2. N. marina, L. ; leaves strongly spinular-serrate. N. major, All. 

 Hickling Broad, Norfolk ; fl. July. — Stem 3-9 in., sparingly branched, toothed 



here and there. Leaves opposite and 3-nate, f-2 in. long ; sheath entire. 

 Flowers dioecious, solitary. Drupe J in., nearly ellipsoid, purplish. — Distrib. 

 Temp, and trop. regions of the Old World. 



OKDER LXXXVIII. CYPERACEiE. 



Grassy or rush-like herbs, usually perennial. Stem solid, often 3-gonous. 

 Leaves with closed sheaths. Flowers 1-2-sexual, in the axils of small 

 bracts (glumes), which are arranged in terete angled or compressed spike- 

 lets, beyond which the anthers and styles project. Glumes concave, often 

 rigid, distichous or inserted all round the rachis, lower of each spikelet 

 often empty. Perianth 0, or of 3-6 or more hypogynous scales or bristles. 

 Stamens 1-6, hypogynous, filaments linear flat ; anthers basifixed, linear, 

 dehiscing inwards, 2-celled, often with a claw at the tip. Ovary 1-celled 

 (in Carex enclosed in a coriaceous utricle, periyynium) formed of 1 folded 

 or 2 connate bracteoles ; style 1 , stigmas 2-3 filiform papillose all over ; 

 ovule solitary, erect, anatropous. Fruit small, indehiscent, compressed 

 or 3-gonous (in Carex enclosed in the perigynium). Seed erect, testa 

 membranous, albumen floury ; embryo minute, lenticular, at the base and 

 outside of the albumen. — Distrib. All climates ; genera 61 ; species 

 2,200. — Affinities obscure. — Properties 0. 



Tribe I. SCIRPE'iE. Spikelets many-fld. Flowers 2-sexual. Perianth 0, or 



of scales or bristles. 



Spikelets compressed; glumes distichous, deciduous 1. Cyperus. 



Spikelet solitary, terete, terminal. Bristles 3-8 included 2. Heleocharis. 



Spikelets usually clustered and lateral. Bristles 0, or 3-8 included..3. Schpus. 

 Spikelets solitary or clustered, terete, terminal. Bristles very 



long flexuous exserted 4. Eriophorum. 



Tribe II. RHYNCHOSPOREiE. Spikelets 1- or few-fld., terete or com- 

 pressed. Flowers upper or all bisexual. Perianth 0, or of bristles. 



Spikelets terete. Bristles slender or 0. Nut beaked 5. Rhynchospora. 



Spikelets compressed ; glumes distichous. Bristles various or 0. 



Nut not beaked 6. Schcenus. 



Spikelets terete. Bristles 0. Nut obtuse 7. Cladium. 



