35 2 CYPERACEAE. Vol. 1. 



18. CAREX L. Sp. PI. 972. 1753.* 



Grass-like sedges, perennial by rootstocks. Culms mostly 3-angled, often strongly phyllo- 

 podic, or aphyllopodic. Leaves 3-ranked, the upper elongated or very short (bracts) and 

 subtending the spikes of flowers, or wanting. Flowers monoecious or dioecious, solitary in 

 the axils of bracts (scales). Spikes either wholly pistillate, wholly staminate, androgynous 

 or gynaecandrous. Perianth none. Staminate flowers of 3 stamens, the filaments filiform. 

 Pistillate flowers of a single pistil with a style and 2 or 3 stigmas, surrounded by the peri- 

 gynium, which completely encloses the achene or is rarely ruptured by it in ripening. Achene 

 3-angled, lenticular or plano-convex. Racheola occasionally developed. 



Species over 1000, widely distributed, most abundant in the temperate zones. Besides the 

 following about an equal number occur in western and southern North America. Specimens can 

 only be satisfactorily determined when nearly or quite mature. Type species : Carex pulicaris L. 



A. Spike one, androgynous; perigynia glabrous, not margined; leaves acicular, their sheaths 

 striate, conspicuously clothing base of stem; stigmas 2 or 3. 1. Nahdinae. 



B. Spikes one to very numerous ; if one, plant not as above. 



1. ACHENES LENTICULAR AND STIGMAS 2 \ LATERAL SPIKES SESSILE ; TERMINAL SPIKE PARTLY PIS- 

 TILLATE, OR IF STAMINATE, THE LATERAL SPIKES SHORT OR HEADS DIOECIOUS. VlGNEA. 



a. Spike one, androgynous, orbicular to short ovoid. 2. Capitatae. 



b. Spikes one to very numerous ; if one, not as above. 



t Rootstocks long-creeping, the culms arising i-few together. 



Spikes several, densely aggregated into a globular ovoid head, appearing like one spike ; perigynia 



membranaceous. 3. Incurvae. 



Spikes not as above ; perigynia not membranaceous. 



Spike one, staminate, pistillate or androgynous. 4. Dioicae. 



Spikes more than one. 



Perigynia not thin or wing-margined, the beak obliquely cut, in age often bidentate. 



Culms becoming decumbent and branching. 5- Chordorhizeae. 



Culms not branching. 6. Divisae. 



Perigynia thin or wing-margined, the beak bidentate. 7. Arenariae. 



tt Culms caespitose, but plants sometimes stoloniferous, or with slender rootstocks. 



* Spikes always androgynous. 



Perigynia strongly compressed, not whitish-green. 



Perigynia i"-2j4" long, the beak not exceeding the body. 



Spikes usually ten or less, green or reddish-brown tinged ; sheaths loose, or if tight not red- 

 dotted or transversely rugulose. 8. Muhlenbergianae. 

 Spikes numerous, yellow or brown ; sheaths tight, the opaque part either red-dotted or trans- 

 versely rugulose. -r 

 Perigynia plano-convex, yellowish ; opaque part of leaf-sheath transversely rugulose, often 



not red-dotted. 9. Multiflorae. 



Perigynia thick, much rounded on outer, somewhat on inner surface, brownish ; opaque 

 part of leaf-sheath red-dotted, not transversely rugulose. 10. Paniculatae. 



Perigynia z"-^]^" long, spongy at base; beak much longer than body. 11. Stenorhynchae. 

 Perigynia scarcely compressed, nearly terete, whitish-green. 12. Tenellae. 



* Spikes gynaecandrous, rarely staminate or pistillate. 

 Perigynia ascending or appressed, the body not margined. 



Perigynia 2" long or less, puncticulate. 13. Canescentes. 



Perigynia longer, not puncticulate. 14. Deweyanae. 



Perigynia body with thin or winged margins. 



Perigynia spongy at base, usually spreading at maturity, thin-margined. 15. Stellulatae. 

 Perigynia not spongy at base, not widely spreading at maturity, wing-margined. 16. Ovales. 



2. Achenes triangular or lenticular ; if lenticular, the lower lateral spikes conspicu- 

 ously peduncled or with staminate terminal spike and elongated lateral spikes. Eu-Carex. 



a. Scales bract-like; achenes strongly constricted at the base. 17. Phyllostachyae. 



b. Scales not bract-like ; achenes not strongly constricted at the base 



t Spike normally one, the perigynia reflexed, or rounded and beakless at the apex. 

 Perigynia rounded at apex, beakless, glabrous ; scales persistent. 18. Polytrichoideae. 



Perigynia beaked, strongly reflexed; scales soon deciduous. 19. Pauciflorae. 



tf Spikes one to many; when one, the perigynia neither reflexed nor rounded. 



* Perigynia both coriaceous and shining, the beak obliquely cut. 20. Nitidae. 

 ** Perigynia not both coriaceous and shining. 



! Spike one; perigynia triangular, glabrous, not flattened. 21. Rupestres. 



! ! Spikes one to many ; when one, perigynia not as above. 



* Perigynia triangular, membranous, closely enveloping the achene, essentially nerveless, or 2-ribbed, 



pubescent or puberulent at least at base of beak, stipitate ; bracts sheathless or nearly so. 

 Spikes normally one. 



Spikes androgynous ; leaf-blades filiform. 22. Filifoliae. 



Spikes dioecious ; leaf-blades not filiform. 23. Scirpinae. 



Spikes normally two or more. 



Perigynia obtusely triangular ; foliage not pubescent. 



Young achenes mitrate at apex ; lowest scales rough-awned ; perigynia not slender-beaked. 



24. Mitratae. 

 Young achenes, lowest scales, and perigynia not as above. 25. Montanae. 



Perigynia acutely triangular ; foliage usually pubescent. 26. Triquetrae. 



00 Perigynia not as above ; or if so, bracts strongly sheathing. 



§ Lowest bract strongly green-sheathing ; perigynia beakless to beaked, entire, oblique or emarginate 

 at apex ; or long-beaked and apex hyaline, becoming bidentate, teeth weak ; achenes triangular, or 

 if rarely lenticular, the perigynia dull and subterete. 



* Text contributed by Mr. Kenneth K. Mackenzie. 



