82 CYPERACEAE. 



Cyperus inflexus Muhl. Annual; stems 1-15 cm. tall, ascending; leaves 

 about 1 mm. wide, often curved, about as long as the stems; bracts much longer 

 than the inflorescence; spikelets ovate-lanceolate, 3-5 mm. long, in dense heads, 

 umbellately arranged on unequal rays; scale green or brownish, the awn-like 

 tip strongly recurved; stamen 1. 



On river banks, rare. Somas Falls, Vancouver Island, Macoun; Kalama, 

 Washington, Piper. 



Cyperus erythrorhizos Muhl. Annual; stems usually 15-60 cm. tall, 

 sometimes much smaller; leaves flat, commonly 2-4 mm. broad, shorter than 

 the stem; involucral leaves 4-8, broad at base, far exceeding the inflorescence; 

 spikelets bright chestnut, linear, 5-6 mm. long, densely crowded into flattened 

 spikes, 1-3 cm. long, the latter umbelled on the unequal branches of the primary 

 umbel; scales oblong, keeled, the green midrib prolonged into a short mucro- 

 nate tip; wings of the rachis separating to the base, forming pairs of small 

 scales. 



River banks, rare in our limits. Vancouver, Washington, Sheldon. 



96. DULICHIUM. 



Tall perennials with cylindrical jointed stems, leafy to the top; 

 lower leaves reduced to sheaths; spikes axillary, peduncled, 

 simple or compound; spikelets 2-ranked, flat, linear, many- 

 flowered; scales 2-ranked; flowers perfect; perianth of 6-9 back- 

 wardly barbed bristles. 



Dulichium arundinaceum (L.) Britt. Stems stout, 30-90 cm. tall, leafy; 

 spikelets linear, 1-2.5 cm. long, 6-10-flowered. 

 Borders of lakes and ponds, common. 



97. RYNCHOSPORA. 



Mostly leafy perennials with rootstocks, erect, 3-angled or 

 cylindrical stems and flat or inroUed leaves; spikelets variously 

 clustered; scales thin, overlapping all around; upper flowers 

 imperfect, the lower perfect; perianth of 1-20, mostly 6, barbed 

 bristles, or none. 



Rynchospora alba (L.) Vahl. Stems slender, 15-40 cm. high; leaves 

 filiform, shorter than the stem; spikelets white, in 1-3 densely crowded corymbs; 

 akene oblong-obovoid, tipped with a flattened triangular tubercle about half 

 as long; bristles longer than the akene. 



In sphagnum bogs, rare in our limits. 



98. ELEOCHARIS. Spike Rush. 



Annual or perennial; stems simple, triangular, quadrangular, 

 terete, flattened or grooved, the leaves reduced to sheaths or the 

 lowest very rarely blade-bearing; spikelets solitary, terminal, 

 erect, several-many-flowered, not subtended by an involucre; 

 scales concave, in a spiral; perianth of 1-12 bristles usually 

 barbed; stamens 2 or 3; akene 3-angled or biconvex; base of the 

 style persistent on the summit of the akene forming a terminal 

 tubercle. 



