478 PROCEEDINGS OF THE AMERICAN ACADEMY. 
+ + Perigynia two-fifths to one-half (.40 to .50) as thick as broad. 
++ Tips of the perigynia distinctly exceeding the scales: spikes short, compact, 
ovoid or short-oblong, brown: perigynia 3 to 3.5 mm. long. 
17. C. Bess, Olney. — Figs. 52, 53. — Culms rather slender, 2 to 
6 dm, high, smooth except at tip: leaves mostly shorter, ascending but 
not stiff, 1.75 to 4.5 mm. wide: spikes 1 to 2 em. long, of 3 to 12 globose 
or ovoid-oblong ascending spikelets 5 to 8 mm. long: perigynia narrowly 
ovate, mostly dull brown and loosely ascending, faintly few-nerved or 
nerveless, 1.5 to 2 mm. broad: scale oblong, bluntly acuminate. — 
Exsicc. fase. ii, no. 12, as nomen nudum. C. tribuloides, var, Bebbii, 
Bailey, Mem. Torr. Cl. i, 55 & in Gray, Man. ed. 6, 620; Britton, 
l. c. 356; Howe, l. c. 42; Cratty, Bull. Lab. Nat. Hist. Univ. Ia., iv. 
359, t. 8.— Low ground, NEwFrouNDLAND to western MaAssacHU- 
SETTS, central New York, Ituinors, the Rocky Mrs., British 
Cotumsia, and northward. June—Aug. 
++ ++ Tips of the perigynia nearly or quite equalled by the scales: perigynia more 
than 3.5 mm. long (sometimes shorter in the slender-spiked silvery green C- 
Soenea). , 
= Perigynia with strong nerves the entire length of the inner face (very rarely 
nerveless). 
a Spike loose and elongated, green or silvery-brown. 
18. C. rornna, Willd. — Figs. 54, 55.— Oulms slender and lax, 
smooth except at tip, 3 to 9 dm. high: leaves soft and loose, pale green 
or glaucous, mostly shorter, 2 to 4 mm. broad: spike linear-cylindric or 
moniliform, erect or flexuous, of 4 to 9 globose or ovoid clavate-narrowed 
appressed-ascending spikelets 6 to 10 mm. long: perigynia ovate, 3 to 4 
mm. long, 1.8 to 2.2 mm. broad, appressed-ascending, finally a little 
spreading. — Enum. 957; Bailey, Mem. Torr. Cl. i. 25, & in Gray, 
Man. ed. 6, 621; Macoun, l. c. 377; Britton 1. c. 357, fig. 867 ; Howe, 
1. c. 43. ©. argyrantha, Tuck. in Herb. distr. (1859). C. adusta, Boott, 
i.e. 119, in part, t. 382, fig. 2, not Boott in Hook. Fl. Bor.-Am. 1 
215. . albolutescens, var. argyrantha, Olney, Exsicc. fase. i. no- 
C. adusta, var. argyrantha, Bailey, Carex Cat. 2.— Dry woods and 
rocky banks, Maine to BririsH Cotumpra and MaryLanp. July. 
Var. perPLexa, Bailey. — Figs. 56, 57. — Coarser, and often taller: 
spikes heavier, mostly nodding, the 6 to 15 spikelets larger, 1 to 1.7 em. 
long, the terminal ones often crowded : perigynia 3.5 to 4.4 mm. long. — 
Mem. Torr. Cl. i. 27, in part, & in Gray, Man. Ed. 6, 621; Britton, 
