35 8 CYPERACEAE. VOL. I. 



Upper scales acuminate or short-cuspidate; perigynia i%"-2" long, less than i" wide; 



spikes linear-cylindric. 144. C. o.vylepis. 



Upper scales sharply cuspidate ; perigynia z"-2 l /2" long, more than i" wide ; spikes linear- 

 oblong or oblong-cylindric. 145. C.Davisii. 

 Lower bract only strongly sheathing; leaves i"-2 n wide. 



Perigynia nearly i" wide, slightly inflated, strongly nerved; lateral spikes scarcely loosely 

 flowered at base. 146. C. aestivaliformis. 



Perigynia about ^2" wide, obscurely nerved; lateral spikes alternately flowered at base. 



147. C.aestivalis. 

 38. DEBILES. 

 Perigynia smooth or puberulent. 



Scales tinged with reddish brown ; perigynia firm, strongly several-nerved ; upper sheaths 



puberulent. 148. C. oblita. 



Scales hyaline with green midrib or somewhat reddish-brown tinged ; perigynia membranous, 



lightly nerved ; upper sheaths glabrous. 

 Perigynia sessile or subsessile ; blades i"2 l /2" wide; scales obtuse to short-cuspidate. 



Perigynia 3"-$" long, the beak subulate; scales white hyaline margined. 149. C. debilis. 

 Perigynia 2j4"-3^+" long, the beak less subulate; scales tawny tinged. 150. C.flexuosa. 

 Perigynia strongly stipitate ; blades 2^/2"-^" wide; scales strongly cuspidate. 151. C. arctata. 

 Perigynia tuberculate -hispid. 152. C. assiniboinensis. 



39. FLEXILES. Represented by i species. 153. C.castanea. 



40. CAPILLARES. Represented by i species. 154. C. capillaris. 



41. LONGIROSTRES. 



Beak of perigynia much shorter than body ; culms not fibrillose at base. 155. C. cherokeensis. 



Beak of perigynia longer than body; culms strongly fibrillose at base. 156. C. Sprengelii. 



42. FRIGIDAE. 



Perigynia rounded at base, its beak very short. 157. C. atrofusca. 



Perigynia strongly narrowed at base, its beak conspicuous, serrulate. 158. C . misandra. 



43. VlRESCENTES. 



Perigynia densely pubescent. 



Leaves exceeding culms; lowest bract setaceous, J4" wide; pistillate spikes oblong cylindric ; 



perigynia obovoid. 159. C.Swanii. 

 Culms exceeding leaves ; lowest bract leaflet-like, J4"-iH" wide; pistillate spikes linear-cylindric ; 



perigynia elliptic. 160. C.virescens. 

 Perigynia glabrous, at least at maturity. 



Perigynia much flattened, rounded at apex, lightly nerved. 161. C. complanata. 



Perigynia swollen, nearly orbicular in cross-section, pointed at apex, coarsely nerved. 



Perigynia i" long, brownish-green; scales not rough-cuspidate. 162. C. caroliniana. 



Perigynia longer, green; scales rough-cuspidate. 163. C.Bushii. 



44. PALLESCENTES. 



Perigynia beakless, lightly nerved. 164. C.pallescens. 



Perigynia short-beaked, strongly nerved. 165. C. abbreviata. 



45. TRACHYCHLAENAE. Represented by i species. 166. C.glauca. 



46. ANOMALAE. Represented by i species. 167. C.scabrata. 



47. LIMOSAE. 

 Perigynia ovoid-elliptic, thick ; pistillate scales broadly oval, obtuse or abruptly minutely pointed ; 



culms obtusely triangular. 168. C.rariflora. 



Perigynia broader, much flattened ; pistillate scales ovate, tapering at apex to long cuspidate ; culms 



sharply triangular 



Strongly stoloniferous ; leaves involute, glaucous, i l /2 r ' wide or less; scales little exceeding peri- 

 gynia. 169. C.limosa. 

 Tufted; leaves flat, not glaucous, wider; scales much exceeding perigynia. 170. C.paupercula. 

 48. SCITAE. Represented by i species. 171. C.Barrattii. 



49. ATRATAE. 



Scales not exceeding perigynia or but slightly so ; sheaths not filamentose. 

 Perigynia not flattened and two-edged. 



Perigynia iJ4" long or less, nerveless, the beak minutely bidentate, the style not prominent. 



1 72. C. Halleri. 



Perigynia longer, two-nerved; beak not bidentate, style prominent. 173. C.stylosa. 

 Perigynia flattened and two-edged. 



Spikes all contiguous, sessile or short-peduncled, erect. 174. C.Parryana. 



Lower spike strongly stalked, often drooping and distant. 175. C. atratiformis. 



Scales awned, noticeably exceeding perigynia; sheaths strongly filamentose. 176. C.Buxbaumii. 

 50. SHORTIANAE. Represented by i species. 177. C.Shortiana. 



51. PALUDOSAE. 

 Perigynia not compressed-triangular, obovoid ; staminate spike one. 



Perigynia strongly ribbed, squarrose, slightly glaucous ; staminate scales tapering into short 



awn; basal sheaths not fibrillose. 178. C.Joori. 



Perigynia obscurely nerved, ascending, very glaucous ; staminate scales abruptly awned ; basal 



sheaths strongly fibrillose. 1 79. C. glaucescens. 



Perigynia compressed-triangular, ovoid ; staminate spikes two or three. 180. C. acutiformis. 



52. RIGIDAE. 

 Culms aphyllopodic. 



Culms very strongly tufted, slender, very rough above ; perigynia beak very short, not twisted. 



Perigynia elliptic, longer than or little exceeded by scales. 181. C.strlcta. 



Perigynia obovate or orbicular, shorter than scales. 182. C.Haydeni. 



Culms tufted and short stoloniferous, stout at base, smooth above ; perigynia beak prominent, 



twisted when dry. 183. C. torta. 



