478 PROCEEDINGS OF THE AMERICAN ACADEMY. 



*- -t- 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. Bebbii, Olney. — Figs. 52, 53. — Culms rather slender, 2 to 

 6 din. high, smooth except at tip : leaves mostly shorter, ascending but 

 not stiff, 1.7 '5 to 4.5 mm. wide : sjnkes 1 to 2 cm. long, of 3 to 12 glohose 

 or ovoid-oblong ascending spikelets 5 to 8 mm. long : perigynia narrowly 

 ovate, mostly dull broivn and loosely ascending, faintly few-nerved or 

 nerveless, 1.5 to 2 mm. broad : scale oblong, bluntly acuminate. — 

 Exsicc. fasc. ii, no. 12, as nomen nudum. C tribuloides, var. Bebbii, 

 Bailey, Mem. Torr. CI. i, 55 & in Gray, Man. ed. 6, 620 ; Britton, 

 1. c. 356; Howe, 1. c. 42; Cratty, Bull. Lab. Nat. Hist. Univ. la., iv. 

 359, t. 8. — Low ground, Newfoundland to western Massachu- 

 setts, central New York, Illinois, the Rocky Mts., British 

 Columbia, 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. 

 foenea). 



= 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. foenea, Willd. — Figs. 54, 55. — Culms 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 If. 

 mm. long, 1.8 to 2.2 mm. broad, appressed-ascending, finally a little 

 spreading. — Enum. 957; Bailey, Mem. Torr. CI. i. 25, & in Gray, 

 Man. ed. 6, 621 ; Macoun, 1. c. 377 ; Britton 1. c. 357, fig. 867 ; Howe, 

 1. c. 43. C. argyrantha, Tuck, in Herb, distr. (1859). C. adusta, Boott, 

 1. c. 119, in part, t. 382, fig. 2, not Boott in Hook. Fl. Bor.-Am. ii. 

 215. C. albolutescens, var. argyrantha, Olney, Exsicc. fasc. i. no. 9. 

 C. adusta, var. argyrantha, Bailey, Carex Cat. 2. — Dry woods and 

 rocky banks, Maine to British Columbia and Maryland. 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 cm. 

 long, the terminal ones often crowded : perigynia 3.5 to If.Jf mm. long. — 

 Mem. Torr. CI. i. 27, in part, & in Gray, Man. Ed. 6, 621 ; Britton, 



