260 



CYPERACEAE 



12. Cyperus erythrorrhizos Muhl. 

 Red-rooted Cyperus. 



Fig. 619. 



Cyperus erythrorrhizos Muhl. Gram. 20. 1817. 

 Cyperus occidentalis Torr. Ann. Lye. N. Y. 3: 259. 

 Cyperus cupreus Presl, Rel. Haenk. 1: 173. 1828. 



1836. 



Annual ; culms tufted, stout or slender, 7-50 cm. 

 tall. Leaves 3-8 mm. wide, rough-margined, those of 

 the involucre 2-7, some of them 3-5 times as long as 

 the inflorescence ; umbel mostly compound ; spikelets 

 linear, subacute, 6-25 mm. long, less than 2 mm. wide, 

 compressed, many-flowered, clustered in oblong, 

 nearly or quite sessile spikes; scales bright chestnut- 

 brown, oblong-lanceolate, mucronulate, appressed, 

 separating from the rachis at maturity, the mem- 

 branous wings of the rachis separating as a pair of 

 hyaline interior scales; stamens 3; style 3-cleft; 

 achene sharply 3-angled, oblong, pointed at both ends, 

 pale, one-half as long as the scale. 



Wet or moist soil, Sonoran Zones; southern California to southern Washington; eastward at lower ele- 

 vations across the continent to Florida and Massachusetts. Either a large race of this species, or a related 

 species occurs along the Colorado River near the boundary. Type locality: Pennsylvania. 



13. Cyperus strigosus L 

 Straw-colored Cyperus 



Fig. 620. 



Cyperus strigosus L. Sp. PI. 47. 1753. 



Perennial by basal tuber-like corms ; culms 

 rather stout, 0.3-0.9 m. tall. Leaves rough- 

 margined, 4-6 mm. w-ide, the longer ones of the 

 involucre much exceeding the umbel ; umbel 

 several-rayed, some of the primary rays often 

 10-15 cm. long, their sheaths terminating in 2 

 bristles ; involucels setaceous ; heads oblong or 

 ovoid ; spikelets flat, linear, 8-19 mm. long, 

 2 mm. wide or less, 7-15-flowered, separating 

 from the axis at maturity ; scales straw- 

 colored, oblong-lanceolate, subacute, strongly 

 several-nerved ; stamens 3 ; style 3-cleft ; ache.ne 

 linear-oblong, 3-angled, acute, about one-third 

 as long as the scale. 



Moist soil. Upper Sonoran Zone; Butte, Mariposa 

 and Amador Counties, California; near springs, west 

 Klickitat County, Oregon; Texas to Minnesota, Flori- 

 da and Maine. Type locality: Virginia. 



14. Cyperus hanseni Britton, sp. nov. 



Hansen's Cyperus. Fig. 621. 



Perennial by short rootstocks ; culms rather stout, 

 smooth, sharply trigonous, 3-5 dm. tall. Leaves 4-6 mm. 

 wide, the basal ones usually shorter than the culm, those of 

 the involucre 1-5 dm. long; umbel compound, the rays few, 

 7 cm. long or less; spikes cylindric, dense, 2-4 cm. long; 

 spikelets yellowish brown, linear, spreading, 6-9 mm. long, 

 about 1 mm. thick, bearing 2^ achenes, falling away above 

 the lower empty scales; fertile scales narrowly oblong; 

 young achene narrowly linear. 



Moist soil. Upper Sonoran Zone; Amador and Shasta Counties 

 and in the valley of the Sacramento River, California. Type col- 

 lected at Jackson, Amador County (George Hansen, No. 821, in 

 1904). 



Referred by S. Watson to Cyperus steuolepis Torr., and included 

 by C. B. Clarke in Mariscus jacquini H. B. K. [Cyperus hernia- 

 phroditus (Jacq.) Standlcy.] 



