wide, closely 10- to 45-flowered, the perigynia ascending; bracts leaflike, the upper 

 reduced, usually shorter than the culms, the sheaths tight; scales broadly ovate, 

 narrower than and about half the length of the perigynia, reddish-brown with 

 hyaline margins and green center; perigynia ovoid or oblong-ovoid, almost terete, 

 scarcely inflated, 3-3.5 mm. long, 1.25-2 mm. wide, many-nerved, light-green or 

 yellowish-green, rounded at the sessile base, rather abruptly contracted into a 

 very short straight entire or minutely bidentulate beak; achenes trigonous, obovoid, 

 sinall, filling only the lower two-thirds of the perigynium, about 1.8 mm. long and 

 1.2 mm. wide. 



Boggy meadows and wet thin soil underlaid by rock, especially in limestone 

 regions, in Okla. (Waterfall); Que. to Alta. and Wash., s. to N.J., Ala., Okla. 

 and Ut. 



80. Carex microdonta T. & H. 



Perennial; rhizomes 2-15 cm. long, 1 mm. thick, brown; culms rising singly or 

 in small tufts from the rhizomes, 9-50 cm. long, 0.7-1.1 mm. thick; leaves mostly 

 crowded at the base, the basal sheaths brown; blades 2-7 mm. broad, shorter than 

 the culm, shortly tapered apically; spikes 3 to 5 per culm, the terminal one 

 staminate (rarely androgynous), usually with the sessile staminate or androgynous 

 second spike attached near its base and overlapping it; rest of spikes usually 

 more remote, erect, on pedicels 2-10 cm. long and nearly all pistillate (the upper 

 one occasionally with a few terminal staminate flowers); staminate spikes promi- 

 nent, 2-5 cm. long, 4-8 mm. thick, often with prominent subpersistent anthers, 

 greenish or brownish, the narrowly obovate scales 3-8 mm. long and brownish to 

 reddish-brown and hyaline with 3 prominent green midnerves; pistillate spikes 1-5 

 cm. long, 5-6 mm. thick, with 20 to 40 close spreading perigynia, the ovate scales 

 acuminate and half as long as the perigynia, reddish-brown with hyaline margins 

 and prominent 3-nerved median; perigynia ovoid to narrowly ovoid, 2.6-3.6 mm. 

 long (including beak), reddish-brown, firm-membranous, with 2 ribs and 12 to 15 

 less prominent nerves, rather closely investing the achene except at the rounded or 

 very shortly tapered base and the conical apex which abruptly passes into the 

 tubular beak (0.5-0.7 mm. long with a minutely 2-toothed apex); achene triangular 

 with concave sides, up to 2.5 mm. long, 1.7 mm. wide, bent-apiculate, jointed with 

 the style which entirely withers after anthesis. 



In moist open places, usually calcareous areas on wet seeping limestone banks 

 and on wet granite ledges in depressions in prairies, in Okla. (Waterfall) and 

 n.-cen. and s.e. Tex., Edwards Plateau, infrequent in e. Tex., rare in the Trans- 

 Pecos, Mar. -May (June-Aug. in Trans-Pecos); Miss., La., Tex.. Okla. and Mo. 



81. Carex amphibola Steud. 



Tufted perennial; culms 15-30 (-40) cm. long, erect; basal sheaths purplish- 

 brown with reduced blades; cauline leaves few. 1.5-3.5 (-4.5) mm. broad, mem- 

 branous, green; spikes usually 4, less commonly 3; terminal spikes inconspicuous 

 and staminate, nearly sessile, 6-20 mm. long, 1.5-2.5 mm. thick, stramineous, the 

 scales broadly hyaline; rest of spikes pistillate (the highest one subtcrminal and 

 sessile at the base of the staminate spike, the others on slender short peduncles and 

 more or less remote), 8-13 (-20) mm. long, about 5 mm. thick, with 3 to 6 (to 10) 

 ascending perigynia which are close enough to overlap (except occasionally the 

 lowermost), the scales with the hyaline broadly ovate main portion about a third 

 to half as long as the perigynia but the abrupt subulate cusp almost equaling it; 

 bracts narrowly foliaceous with definite close sheaths, the blades greatly surpassing 

 the spikes; perigynia turgidly to slenderly obovoid, in transection nearly round 

 when fresh but less so after drying, often obtusely triangular, 4-5 mm. long, 

 inflated, brown-membranous, in the lower half with about 50 or 60 nerves which 



554 



