212 NORTH AMERICAN FLORA [Vovjmk 17 



4r-10 cm. long, the lower shorter and more spreading, 4-7 mm. wide, abruptly acuminate, 

 rounded at the base and wider than the sheath, sparsely papillose-ciliate, at least toward the 

 base, scabrous on the upper surface; panicles slender, interrupted, their branches erect, the 

 branchlets bearing 1-3 short-pediceled spikelets, the setiform prolongation of the axis usually 

 about as long as the spikelets, sometimes twice as long; spikelets 3-3.2 mm. long, 1.7-1.8 mm. 

 wide, obovate, subacute, turgid, strongly nerved; first glume clasping, half the length of the 

 spikelet, pointed, 5-7-nerved; second glume and sterile lemma subequal, scarcely covering the 

 fruit, 5-7-nerved, the glume obscurely reticulate toward the summit; fruit 2.7-2.8 mm. long, 

 1.6-1.7 mm. wide, ob ovate-elliptic, abruptly acute, very turgid. 



Type locality: Elsordo, Zapata County, Texas. 

 Distribution: Southern Texas. 

 Illustration: Contr. U. V S. Nat. Herb. 15: /. 9. 



7. Panicum geminatum Forsk. Fl. Aegypt.-Arab. 18. 1775. 



Paspalum appressum I,am. Tab. Encyc. 1: 176. 1791. 

 Digitaria appressa Pers. Syn. PI. 1: 85. 1805. 

 ? Digitaria afjinis R. & S. Syst. Veg. 2: 470. 1817. 

 Panicum beckmanniaeforme Mikan; Trin. Neue Entdeck. 2: 83. 1821. 

 Panicum truncatum Trin. Gram. Pan. 130. 1826. 

 ? Panicum affine Nees, Agrost. Bras. 113. 1829. 

 Panicum brizaeforme J. Presl, in Presl, Rel. Haenk. 1: 302. 1830. 

 Panicum carnosum Salzm.; Steud. Syn. Gram. 60, as synonym. 1854. 



Panicum glomeratum Buckl. Prel. Rep. Geol. & Agr. Surv. Tex. App. 3. 1866. Not P. glomeratum 

 Moench, 1794. 



Panicum appressum lam.; Doell, in Mart. Fl. Bras. 2 2 : 184. 1877. Not P. appressum Forsk. 

 1775. 



Plants glabrous throughout; culms cespitose, usually numerous, 25-80 cm. high, spreading 

 from a more or less decumbent base, scarcely succulent ; leaf-sheaths usually overlapping, rather 

 close; ligule ciliate, 1 mm. long; blades 10-20 cm. long, 3-6 mm. wide, rather stiffly spread- 

 ing or erect, flat, or involute toward the apex, somewhat scabrous on the upper surface; 

 panicles short-exserted or included at the base, 12-30 cm. long; axis angled, smooth except 

 toward the summit; racemes 12-18, erect or narrowly ascending, the lower rarely distant 

 more than their own length, the upper gradually approximate, the lower 2.5-3 cm. long, the 

 upper successively shorter, the axis usually ending in a more or less well-marked, pointed pro- 

 longation; spikelets subsessile, 2.2-2.4 mm. long, 1.4 mm. wide, turgid, abruptly and minutely 

 pointed; first glume about one third the length of the spikelet, truncate or obtuse; second 

 glume nearly as long as the fruit (exceeded only by the point of latter), 5-nerved; sterile lemma 

 5 -nerved, abruptly pointed, equaling the fruit and like the second glume very faintly reticu- 

 late toward the summit, inclosing a hyaline palea and usually an abortive staminate flower; 

 fruit 2.2 mm. long, 1.2 mm. wide, elliptic, abruptly pointed, strongly transversely rugose. 



Type locality: Rosetta, Egypt. 



Distribution : Florida and Texas, and southward through the West Indies and Mexico to tropical 

 South America; also in the warmer parts of the Old World. 



Illustrations: Rep. Mo. Bot. Gard. 10: pi. 16; Field Columb. Mus. Publ. Bot. 3: 34 (as 



P. paspalodes) ; Contr. U. S. Nat. Herb. 15: /. 11. 



This species has been erroneously referred to Panicum paspalodes Pers., of India. 



8. Panicum paludivagum Hitchc. & Chase, Contr. U. S. Nat. Herb. 



15: 32. 1910. 



Plants glabrous throughout; culms elongate, from a. long, creeping base, rooting at 

 the nodes, rather soft and succulent, as much as 2 meters long, the lower submerged 

 portion loosely branching, the intern odes, except the uppermost, somewhat swollen, the 

 nodes constricted and often dark-colored; leaf-sheaths papery and more or less inflated, 

 especially the lower, mostly deciduous from the submerged portion; ligule ciliate, about 1 mm. 

 long; blades 15-40 cm. long, conduplicate at base, flat above, long- acuminate, rather lax, very 

 scabrous on the upper surface, smooth below, the lower much reduced or rudimentary; panicles 

 usually overtopped or equaled by the leaves, 25-35 cm. long; axis angled, smooth; racemes 

 12-15, erect, the lower distant, 3 cm. long, the upper gradually approximate and shorter, the 

 axis ending in a rudimentary spikelet or sometimes in a short, slender-pointed prolongation; 

 spikelets appressed to the angled rachis, 2.8-3 mm. long, 1.4-1.6 mm. wide, narrowly ovate, 



