incomplete septa becoming conspicuous, the upper part involute; inflorescence 

 (excluding bracts) 5-15 (-22) cm. long, of 3 to 10 extremely unequal primary 

 peduncles, the shorter ones each bearing a head of spikelets, the longer ones often 

 with several short secondary peduncles each bearing a head; each head with 5 to 

 13 spikelets; bracts 3 to 5, the longer ones much-exceeding the inflorescence; 

 spikelets 3-15 mm. long, 2.5-4 mm. broad, with 6 to 20 flowers, viscid, grayish- 

 ochraceous turning grayish-brown at maturity, the axis persistent and remaining 

 intact even after the scales and achenes have fallen, wingless; scales firm. 3-4.2 

 mm. long, with 3 strong nerves close together on the weakly keel-like median and 

 farther apart on each side 2 or 3 less conspicuous ones (7 to 9 altogether), the 

 very sharp tip slightly excurved, the lower sides not decurrent (the scales measured 

 as folded in the spikelet is 1-1.2 mm. broad); stamens 3; achene 1.4-1.8 mm. 

 long, black at maturity, trigonous, widest near the apex and long-tapered to the 

 base. 



In moist calcareous soil, edge of lakes, ponds and tanks, and wet gravel-sand 

 of creek beds, frequent in s.e. Tex. and Rio Grande Plains, infrequent to rare in 

 Edwards Plateau and Trans-Pecos, Aug.-Nov., rarely in spring or early summer; 

 W.I., Trin., C.A., Mex., Fla., La. and Tex.; a var. major Kukenth. in Peru. 



33. Cypenis oxylepis Steud. 



Tufted perennial; culms 3-7 dm. long, erect; leaves viscid, crowded near the 

 base, basally stramineous splotched with red, somewhat spongy when fresh and 

 upon drying the incomplete septa becoming conspicuous, the upper part involute; 

 inflorescence (excluding bracts) 5-15 cm. long, of 3 to 10 extremely unequal 

 primary peduncles, the shorter ones each bearing a head of spikelets. the longer 

 ones often with several short secondary peduncles each bearing a head, each head 

 with 6 to 18 spikelets; bracts 3 to 5, the longer ones much-exceeding the in- 

 florescence; spikelets 8-22 mm. long, 2.5-3.5 mm. broad, with 10 to 24 flowers, 

 viscid, grayish-yellow becoming at maturity a rich golden-brown, the axis persis- 

 tent and remaining intact even after the scales and achenes fall, wingless; scales 

 firm-membranous, 3.3-3.7 mm. long, with 3 strong nerves together on the weakly 

 keel-like median and farther apart on each side 2 less conspicuous ones (7 

 altogether), the sharp point very slightly excurved. the lower sides not decurrent 

 on the axis (the half-scale measured as it is folded in the spikelet is 0.8 mm. 

 broad); stamens 3; achene 1.4-2 mm. long, dark-brown at maturity, trigonous, 

 nearly cylindric or very slightly thickened in the upper part and long-tapered 

 below, capped by the beaklike persistent style base about 1 mm. long. 



Infrequent in coastal s.e. Tex. (Harris, Nueces, Refugio and San Patricio cos.) 

 in clay ditches and ponds, May-Aug.; Arg., Parag., Ecu., Col., Br. Gui., Jam., 

 Virg. I., Oax., Sin., Son., Tex. and La. 



34. Cypenis rotundus L. Nut-grass, tulillo. Fig. 233. 



Perennial forming colonies with creeping rhizomes about 1 mm. thick, at 

 intervals with tuberlike thickenings to 1 cm. thick; culms 8-30 (-75) cm. long, 

 just beneath the inflorescence 0.8-1.8 mm. thick; leaves crowded in the basal few 

 cm., much shorter than the culm and usually spreading; inflorescence 3-11 cm. 

 long, of 3 to 8 extremely unequal peduncles each hearing a (rarely compound) 

 cluster or short spike of divaricate spikelets. each cluster or spike with 3 to 9 

 spikelets, the total inflorescence with 20 to 65 spikelets; bracts usually about 3 or 

 4 and about as long as the inflorescence; spikelets 4-30 mm. long. 1-2 mm. broad, 

 laterally much-comnressed, with 12 to 36 flowers; scales keeled, straight, dark- 

 reddish, dark-purplish or dark-purplish-brown, 3-3.5 mm. long, with about 7 

 paler nerves crowded near the median so that each of the halves is nerveless in 

 the marginal half to five eighths the width, the sides decurrent basally as hyaline 



454 



