486 PROCEEDINGS OF THE AMERICAN ACADEMY. 
+ + Perigynia broadest near the middle, tapering to a narrow base and a 
smooth beak. 
29. C. seorsa, E. C. Howe. — Figs. 106 to 109. — Culms soft, in 
loose stools, 3.5 to 6.5 dm. high: leaves shorter, soft, pale, 2 to 4 mm. 
broad: spikes 2.5 to 7 cm. long, of 2 to 6 mostly remote subglobose or 
oblong 6- to 20-flowered green spikelets 3.5 to 7 mm. long, the ter- 
minal one usually with a long-clavate base, the lower often subtended 
by a setiform bract: perigynia very thin and conspicuously nerved, ellip- 
tic-ovate, with a very short smooth beak and a narrow substipitate base, 
2.7 mm. long, 1.9 mm. broad, wide-spreading or recurved, much exceed- 
ing the acutish scales. — 48 Rep. N. Y. Mus. Nat. Hist. 40. ©. canes- 
cens, var. vulgaris, Deane, Met. Park FI. 95, not Bailey. — Wet woods 
and swamps, from Middlesex Co., MassacuusetTts to Suffolk and 
Oneida Cos., New York, south to DeLaware. May, June. 
Elongatae, Kunth. Spikelets remote or approximate in a simple 
elongated or short inflorescence. Staminate flowers at the base of the 
spikelets. Perigynia ascending when mature, glabrous, ovate to oblong or 
lanceolate, plano-convex, beaked or beakless, not thin-winged. 
* Perigynia more or less roughened or serrulate on the upper edges (sometimes 
smooth in exceptional forms of C. canescens ; and by exception obscurely toothed 
in rare individuals of C. tenuiflora). 
+ Perigynia broadest at the rounded or subcordate base. 
30. C. arcra, Boott. — Figs. 110 to 113. — Pale green or somewhat 
glaucous: culms very soft, in loose stools, 1.5 to 6 dm. high, often over- 
topped by the soft flat leaves 2.5 to 4 mm. broad: spike oblong-cylindric, 
of 5 to 13 ovoid or oblong closely approximate or slightly remote spikelets 
6 to 11 mm. long: perigynia ovate, with a rather definite beak, strongly 
nerved on the outer, faintly on the inner face, 2 to 3 mm. long, 1.2 to 
1.5 mm. broad, somewhat exceeding the acute, often brown-tinged, 
scales. — Ill. iv. 155, t. 497; Macoun, l. c. 124; Britton, 1. c. 352, fig. 
850. ©. canescens, var. polystachya, Boott in Richards. Arct. Exped. ii. 
344; Bailey, Proc. Am. Acad. xxii. 144, Mem. Torr. Cl. i. 75, & in 
Gray, Man. ed. 6, 619. C. Kunzei, Olney, Proc. Am. Acad. viii. 406 
(excl. syn.). ©. canescens, var. oregana, Bailey, Mem. Torr. Cl. i. 75. 
— Wet woods, alluvial thickets and swales, from the larger river-valleys 
of Marne and Quesec, Lake Champlain, Vermont, and the Adirondack 
Mts., New Yor« to Lake Nipigon, Onrarro, and British CoLuMBIA, 
south to Micuigan, Minnesota, and the coast and mountains of 
_Wasuineton and Orecon. June—Aug. 
