Herbs, perennial, rhizomatous. Culms basally cormlike, trigonous, (8-)15-40(-60) cm × (0.4-)0.8-1.5(-2) mm, glabrous or sparsely to densely scabridulous to minutely scabrid on angles or usually on surface, just proximal to bracts or over distal few centimeters. Leaves (1-)3-4, V-shaped, (7-)15-25(-40) cm × 1-3(-5) mm, sparsely minutely scabridulous on margins and keel in distal 1/3, otherwise glabrous. Inflorescences: spikes 1-3, sessile (occasionally 1 spike on peduncle 5-20 cm, produced from axil of distalmost leaf), loosely cylindric to oblong-ovoid, (9-)15-30(-45) × (3-)8-15(-18) mm; bracts 2-3(-7), longest erect, or very nearly so, others spreading, (1-)3-20(-26) cm × (0.5-)1-3(-5) mm; rays (1-)2-6(-11), (1-)2-7(-12) cm, in some depauperate plants rays less than 1 cm; rachilla ± deciduous, wingless. Spikelets (4-)8-25(-35), oblong-ellipsoid to linear, compressed-quadrangular, (2-)7-11(-15) × (2-)2.4-3.2(-3.5) mm; floral scales (1-)4-8(-14), laterally dull whitish, stramineous, or light brown, or reddish brown to deep red, often red-dotted especially near keel, medially greenish, broadly ovate-deltate to ± orbiculate, laterally strongly 3(-4)-ribbed, medially weakly 1-3-ribbed, (1.6-)1.8-2.4 × (1.8-)2.2-2.8 mm, margins clear, erose especially apically, apex obtuse, tipped with straight mucro 0.1-0.2(-0.3) mm. Flowers: anthers 0.4-0.6 mm; styles 0.4(-0.8) mm; stigmas 0.6-1 mm. Achenes finely reticulate with isodiametric cells, this layer gradually wearing away to reveal inner brown to reddish brown layer, stipitate, ovoid to obovoid, 1.4-1.6(-1.9) × 1-1.3(-1.4) mm, base cuneate to ± attenuate, stipe 0.1-0.2 × 0.2 mm, apex obtuse, slightly apiculate, inner layer papillose.
Fruiting summer. Clearings in montane forests; 1000-2500 m; Ariz., N.Mex., Tex.; Mexico.
Cyperus sphaerolepis has long been known by the synonym C. rusbyi and has been treated as a variety of C. fendlerianus. Specific status for C. sphaerolepis is supported by B. G. Marcks (1972) and G. C. Tucker (1994).
Common Name: Rusby's flatsedge
Duration: Perennial
Nativity: Native
Lifeform: Graminoid
General: Rhizomatous perennial 15-40 cm tall, with rhizomes 1-2 cm long, 2-5 mm in diameter, densely covered with light brown to reddish brown scales, with stems 1-2 cm apart.
Vegetative: Culms 1-1.5 mm in diameter, three-ranked, smooth or sparsely to densely scabrous on angles on the surface, just below the bracts; leaves 3-4, 15-25 cm long, 1-3 mm wide, v-shaped, sparsely rough to the touch on the margins and keel in the distal third, ot
Inflorescence: Spikes 1-3, sessile, occasionally a single spike borne on a peduncle 5-20 cm long from the axil of the uppermost leaf; spike 15-30 mm long, 8-15 mm wide, loosely cylindric to oblong-ovoid; rachis 10-30 mm long, spikelets at an oblique angle, oriented toward the summit of the spike; 8-25 spikelets, 7-11 mm long, 2.5-3 mm wide, broadly ovate to suborbiculate with an obtuse apex, straight mucro minute, with a tuft of prickles at tip, laterally 3 nerved, dull whitish, light brown to reddish or deep red brown. Achenes about 1.5 mm long, a little over 1 mm wide, ovoid to obovoid, obtuse apex, brown to reddish brown.
Ecology: Usually in clearings in forests, meadows, swales, dry streambeds and disturbed soils from 3,500-8,500 ft (1067-2591 m); flowers July-September.
Notes: Similar to C. fendlerianus, but distinguished by having at least one pedunculate or rayed spike in inflorescence, the shorter scales with shorter and straighter mucros, and also by the erect leading bract of the inflorescence.
Ethnobotany: Unknown
Etymology: Cyperus is from the Greek word meaning sedge, while sphaerolepis comes from sphaira meaning globe, and lepis meaning scale.
Synonyms: Cyperus fendlerianus var. debilis, Cyperus rusbyi, Cyperus squarrosus var. squarrosus
Editor: SBuckley, 2010
