PANKE.E. 115 



15. P. Curtisii Steud. Syn. PI. (Jriun. (50 (1855), not Chapni. 

 (1800). 



P. Waltvri Ell. Bot. S. C. and Oa. 1: 115 (1810). 



P. laviniitum Torr. Bost. Joiiru. Nat. llist. 1: 137 (1835), not 

 Presl (1830). 



P. diyUarUndex Carpenter, ex M. A. Curt, in Am. Jonru. Sc. 

 (II.) 7:410 (1849), not Rasp, ex Steud. Noni. 



Culms slender, rigid, often rooting at the lower node.s. 100-130 

 cm. high. Sheaths sometimes hairy ; blades smooth, rigid, 15-20 

 cm. long, 10-15 mm. wide. Panicle slender, simple. 15-18 cm. 

 long. Spikes appressed, the lower 2-4 cm. long. 5-8 cm. distant, 

 the upper crowded and very short, rachis slender, flexuous, trian- 

 gular. Spikelets mostly in pairs on pedicels shorter than them- 

 selves, each containing a staminate and a ]ierfect flower, ovate- 

 lanceolate, 2-2.5 mm. long; first glume half as long as the spikelet, 

 acute, 3-nerved, second ovate. 5-nerved: floral glume of the sterile 

 floret like the second empty glume ; palea oval, as long as its 

 glume 2-nerved; fertile floret ovate-lanceolate, acute, much like 

 the preceding. 



Florida, Curtim 3585. 



Ponds and swamps. North Carolina to Florida and Texas. 



10. P. obtusum II. B. K. Xov. Gen. 1: 98 (1815). 



A glabrous tut'tod grass, decumbent or creeping, hairy at the 

 nodes and near the ligule, 15-40 cm. high. Loaf-blades firm, 

 slender, 5-12 cm. long, 2-4 mm. wide. Spikes 3-5. mostly simple, 

 erect, usually longer than the internodes, 1-4 cm. long, rachis fili- 

 form, triangular, flexuose. Spikelets mostly in pairs, smooth, 

 oval, obtuse, 3 mm. long, first glume ono-tiiird sjiortcr than the 

 spikelet, ovate with 5 green nerves, second longer, 7-9-nerved ; 

 floral glume of the staminate fioret like the first em])ty glume, first 

 palea ovate, 2-nerved. Stamens 3. Fertile fioret clli])tical. 



Texas, Jones 3103 : Arizona, T. S. Uvpt. At/riciil. 85 from 

 Lemmon. 



Texas, Arizona, aiul Mexico. 



17. P. prostratum Lam. 111. 1:171 (1783). P. apspifosmn Sw. 

 PI. Ind. Occ. 1: 140 (1797), not Spreng. 



