204 CYPERACEAE (SEDGE FAMILY) 



dm. high, scabrous above ; leaves 1-2 mm. wide, flat, about half 

 as long as the culms; heads slender, 1-2.5 cm. long, of 2-7 remote 

 appressed-ascending spikes; spikes either staminate (clavate), 

 androgynous, or pistillate (ovoid) ; bracts ovate, concave ; glumes 

 ovate, subspathiform, emarginate at tip, more or less marked with 

 green and brown ; style with 2 elongate branches, the slender 

 base becoming chartaceous and subpersistent, finally separating 



K elach - from tlie truncate subterete nerveless pale achene (1.2-1.5 mm. 



car y " long); stamens 2, the anthers much exceeding the filaments. 

 Wet banks of Aroostook R., Me.; local. June, July. FIG. 339. 



18. CAREX [Ruppius] L. SEDGE 



Flowers unisexual, destitute of floral envelopes, disposed in spikes ; the 

 staminate consisting of three stamens, in the axil of a bract, or scale ; the pistil- 

 late comprising a single pistil with a bifid or trifid style, forming in fruit a hard 

 achene, which is inclosed in a sac (perigynium) borne in the axil of a bract, or 

 scale. Staminate and pistillate flowers borne in different parts of the spike 

 (spike androgynous"), or in separate spikes on the same culm, or rarely the 

 plant dioecious. Perennial grass-like herbs with mostly triangular culms, 

 3-ranked leaves, and spikes in the axils of leafy or scale-like bracts, often aggre- 

 gated into heads. An exceedingly critical genus, the study of which should be 

 attempted only with complete and fully mature specimens. 1 (The classical 

 Latin name, of obscure signification ; derived by some from Kelpeiv, to cut, on 

 account of the sharp leaves as indicated in the English name Shear-grass. ) 



1. Spikes mostly uniform and sessile, bearing the staminate flowers at base or 

 apex or sometimes scattered amongst the pistillate ; stigmas 2 and achenes 

 lenticular. Vf GNEAE [Beauv.] Koch. (For 2, see p. 209.) 



A. Staminate flowers scattered or at the base of the spikes (only in 

 exceptional individuals and in the often dioecious (7. gynoerates 

 and C. exilits the entire spike staminate) . 

 . PERIGYNIA WITH THIN OK WINGED MARGINS C. 



C. Perigynia ascending, the tips only sometimes wide-spreading or 

 recurved, not spongy at base, the margins winged at least 

 toward the beak D. 

 D. Bracts wanting or setaceous, if broad at most twice as long as 



the inflorescence E. 

 E. Strongly stoloniferous ; culms rising from an elongated 



rootstock ; perigynia firm, 5-6 mm. long . . 4. C. siccata. 



E. Not strongly stoloniferous ; culms solitary or in stools F. 

 F. Perigynia less than 2 mm. broad G. 

 O. Perigynia 5 mm. or more long If. 

 H. Perigynia 7-10 mm. long ; spikes long-cylindric, 



pointed, 1.5-2.5 cm. long 1. O. muskingumensis. 



H. Perigynia shorter (or, when exceptionally 7 mm. long, 



in shorter spikes) /. 

 /. Perigynia half as broad as long, plump, nerveless 



or obscurely short-nerved on inner face . . 22. C. aenea. 

 I. Perigynia one third as broad as long J. 

 J. Perigynia thin, scale-like, scarcely distended over 

 the achenes, distinctly nerved on the inner 

 face and prominently exceeding the subtend- 

 ing scales. 

 Leaves at most 3 mm. wide ; spikes 3-9, glossy 



brown or straw-colored, pointed. 

 Inflorescence oblong-ovoid or subcylindric, 



with ascending approximate spikes . . 2. C. scoparia. 

 Inflorescence moniliform . . (2) C. scoparia, v. moniliformis. 

 Inflorescence subglobose or broad-ovoid, 



spikes crowded and divergent . . (2) C. scoparia, v. condensa. 

 Leaves more than 3 mm. wide; spikes 8-14, 



green or dull brown, blunt . . . 3. O. tribuloides. 



1 The perigynial characters are here based on study of mature plants. In gen- 

 eral the perigynia at the tip of the spike are less characteristic than those nearer 

 the middle ; and, if possible, the latter alone should be osed in critical comparisons. 



