54 CYPEEACEAE. 



mainly brown, strongly separate and forming a flexuous head, 4-8 dm. long: 

 bracts small or obsolete : scales ovate, thin, acute or short-awned : perigynia 

 ovoid, light-brown, 2.5-3 mm. long, hard, plump, nearly flat on inner face, 

 usually exceeded by the scales, the beak rather shorter than, the body. — M. 

 Rare, in the Dillerville swamp. — Limestones. — Sum. 



8. C. stipata Muhl. Leaves green; blades flat, 4—8 mm. wide; sheaths strongly 

 septate, the opaque part thin, strongly transeversely rugulose, easily breaking: 

 culms stout at base, sharply 3-angled, 4-12 dm. tall: bracts bristle-form or 

 wanting: spikes numerous, yellowish-brown, in a terminal oblong cluster 3-10 

 cm. long, the staminate flowers few, always terminal: scales ovate or lanceolate, 

 acuminate, much shorter than the perigynia : perigynia lanceolate, 4-5 mm. 

 long, each tapering into a rough flattened 2-toothed beak 1-2 times as long as 

 the body. — Common, in meadows and swamps. — Sum. 



9. C, laevi-vaginata (Kiiken.) Mackenzie. Leaves light-green; blades flat, 

 3-6 mm. wide; sheaths sparingly septate, the opaque part thickened at the 

 mouth, not transversely rugulose, not easily breaking: culms little thickened at 

 the base, sharply 3-angled, 4-8 dm. tall: bracts inconspicuous: sjaikes numerous, 

 yellowish-green, in a terminal linear-oblong or oblong cluster, 2.5-G cm. long, 

 the staminate flowers few, always terminal: scales ovate or lanceolate, acumi- 

 nate, much shorter than the perigynia: perigynia lanceolate, 4.5-5 mm. long, 

 each tapering into a rough flattened 2-toothed beak longer than the body. — M. 

 Frequent, in meadows and swamps. — Limestones. — Sum. 



10. C. 'bromoides Schk. Leaves soft ; blades 2 mm. wide or less, flat : culms 

 slender, very rough above, 2—6 dm. long: bracts subulate or bristle-form, the 

 lowest commonly elongated: spikes 3-7, narrowly oblong-cylindric, 7-18 mm. 

 long, erect or ascending, mostly close together, the staminate flowers either 

 basal, basal and terminal, or both: scales oblong-lanceolate, green, brownish 

 tinged, obtusish to acuminate, shorter than the perigynia : perigynia linear- 

 lanceolate, pale, little margined above, strongly several-nerved, 4-5.5 mm. long, 

 the inner face flat, the tapering rough 2-toothed beak at least \ as long as the 

 body. — M. Rare, in wet woods. — Limestones. — Sum. 



11. 0. sterilis Willd. Leaves shorter than the culm; blades 1-2 mm. wide: 

 culms slender, 2-4.5 dm. tall, rough, at least above: spikes 3-8, subglobose or 

 short-oblong, about 5 mm. thick: staminate flowers usually numerous at the 

 bottom of the upper spike, or whole spikes staminate, or plants occasionally 

 quite dioecious: scales ovate, shorter than the perigynia, obtuse or acutish: 

 perigynia ovate, compressed, appressed or ascending, or in extreme age spread- 

 ing, little exceeding scales, rough edged above, the teeth short and suture on 

 inner face little developed, 2.5 mm. long, 1 mm. wide, several-nerved on outer 

 face, obsoletely nerved on inner face, each tapering into a sharp-edged 2-toothed 

 rough beak not 3 as long as the body. — M. Rare, in swamps. — Limestones. 

 ■ — Early sum. 



12. C. interior Bailey. Similar to C. Leersii in habit. Leaves shorter than the 

 culm; blades 1-2 mm. wide: culms slender, wiry, 2-6 dm. tall: spikes 2-4, 

 nearly globular, 4 mm. in diameter: scales ovate, obtuse to acutish, conspicu- 

 ously shorter than the perigynia: perigynia soon spreading, ovate, 2.25 mm. 

 long or less, faintly few-nerved on the outer face, nearly nerveless on the inner, 

 plump, each abruptly contracted into a roughened 2-toothed beak ^ to i as long 

 as the very sparingly serrulate body, the teeth very short and suture on inner 

 face not conspicuous. — M. Rather rare, in wet places. — Limestones. — Sum. 



13. C. Leersii Willd. Light-green: leaves usually exceeding culm; blades 0.5- 

 1 mm. wide : culms very slender, 1.5-3 dm. tall, smooth or very nearly so 

 throughout: spikes 2-5, 2-8-flowered, more or less strongly separate: staminate 

 flowers at base of terminal spike conspicuous: scales ovate, acute or short- 

 cuspidate, much shorter than perigynia: perigynia light-green, 3-3.5 mm. long, 

 plano-convex, obscurely nerved on inner face, widely spreading, tapering or 



