CYPERACEAE (SEDGE FAMILY) 



183 



248. E. Engelmannl 

 Spikelet x 2%. 

 Achene x 10. 



249. E. palustris. 

 Spikelet X 2. 

 Achene x 10. 



high ; spikelet cylindric, 6-20 mm. long, 2-4 mm. thick, acutish ; scales close- 

 appressed, brown; achenes with broad much flattened tubercle; bristles about 

 equaling the achene. Local, Mass, to Mo. FIG. 248. Var. 

 DKTONSA Gray. Bristles wanting or rudimentary. More 

 frequent, Mass, to Neb., s. to Pa., Ind., and Ariz. 



12. E. palustris (L.) R. & S. Culms nearly terete, striate, 



0.1-1.5 in. high; spikelet slender, sub- 

 cylindric, pointed, many-flowered; scales 

 ovate-oblong, loosely imbricated, reddish- 

 brown with a broad and translucent 

 whitish margin and a greenish keel, the 

 upper acutish, the lowest rounded and 

 often enlarged ; achene obovoid, some- 

 what shining, crowned with a short ovate 

 or ovate-triangular flattened tubercle, 

 shorter than the usually 4 bristles. 

 Very common and variable, either in 

 water, where it is rather stout and tall, or in wet grassy 

 grounds, where it is slender and lower. (Eurasia.) FIG. 

 249. Var. GLACCESCENS (Willd.) Gray. Culms slender or 

 filiform ; tubercle narrower, acute, beak-like, sometimes half as long as the 

 achene. With the type. Var. CALVA (Torr.) Gray. Bristles none ; tubercle 

 short, but narrower than in the type. Local. Var. V!GENS 

 Bailey. Culms very stout, rigid ; achene more broadly obovoid. 

 Lake margins, northw. 



13. E. acicuiaris (L.) R. & S. Culms finely capillary, 3-10 

 cm. high (becoming much elongate when submersed), more or 



less ^-angular; spikelet 2-6 mm. long; scales 

 ovate-oblong, rather obtuse (greenish with purple 250. E. acicularis. 

 sides) ; achenes obovate-oblong, only the lowest Spikelet x 2. 

 maturing, with 3-ribbed angles and 2-3 times as Achene x 10. 

 many smaller intermediate ribs, also transversely 

 striate, longer than the 3-4 very fugacious bristles ; tubercle coni- 

 cal-triangular. Muddy shores, across the continent. (W. L, 

 Eurasia.) FIG. 250. 



14. E. W61fii Gray. Culms slender (2-3 dm. high), from very 

 small creeping rhizomes, 2-edged; spikelet slender-ovoid, acute, 

 0.5-1 cm. long ; scales ovate-oblong, obtuse, scarious, pale purple ; 

 achene pyriform, shining, with 9 nearly equidistant obtuse ribs 

 having transverse wrinkles between them ; tubercle depressed, truncate, more 

 or less apiculate ; bristles none. Wet prairies, 111., Minn., and la. FIG. 251, 



15. E. t6rtilis (Link) Schultes. Culms tufted from fibrous 

 roots, sharply triangular, capillary, twisting when dry ; spike- 

 let turgid-ovoid, 3-6 mm. long, few-flowered ; scales firm- 

 membranaceous, persistent, ovate ; bristles stout, barbed, 

 as long as the striate and pitted-reticu- 

 late achene and its conic-beaked tuber- 

 cle.^. J. to Fla. FIG. 252. 



16. E. tubercul&sa (Michx.) R. & S. 

 Similar; culms flattish, striate; spike- 

 let 6-13 mm. long, many-flowered ; 

 tubercle flattish - cap - shaped. Wet 

 sandy soil, from Mass, along the coast 

 to Fla. FIG. 253. 



17. E. Torreyana Boeckl. Tufted culms capillary. 

 1-6 dm. high ; spikelet small (2-5 mm. long'), sometimes 

 proliferous, the one or more short new culms from the 

 axil of its lowest scale, which persists as an herbaceous 

 bract; scales thin, ovate, acutish, whitish-green and 

 brown ; achene tiny, white, with sharp angles and a short 



251. E. Wolfii. 

 Spikelet X 2. 

 Achene x 10. 



252. E. tortilis. 

 Spikelet x 2. 

 Achene x 10. 



253. E. tuberculosa. 

 Spikelet x 2. 

 Achene x 10. 



