Part 3, 1915] POACEAB 



233 



papillose-hirsute (the greater number of papillae without hairs); ligule about 0.5 mm. long; 

 blades ascending or spreading, 10-25 cm. long, 6-12 mm. wide, linear, scarcely narrowed to the 

 rounded base, very sparsely papillose-pilose on the upper surface, glabrous beneath or with a 

 few papillae; panicles short-exserted or included at the base, 20-25 cm. long, 2-5 cm. wide, the 

 branches raceme-like, the lower solitary, distant, the middle and upper opposite or verticillate, 

 the rachises and upper part of the main axis with stiff hairs slightly exceeding the short-pedi- 

 celed, secund, approximate, but scarcely crowded spikelets; spikelets mostly in pairs, 2.5 mm. 

 long, 0,9 mm. wide, pointed, strongly nerved, the nerves minutely scabrous toward the sum- 

 mit; first glume about half the length of the spikelet, pointed; second glume shorter than the 

 sterile lemma, both slightly exceeding the fruit, the sterile palea obsolete; fruit 2.1 mm. long, 

 0.8 mm. wide, acute, thin in texture, scabrous toward the summit. 



Type locality: Jalapa, Vera Cruz. 



Distribution: Vera Cruz. 



Illustration: Contr. U. S. Nat. Herb. 15: /. 106. 



A- 



64. Panicum stagnatile Hitchc. & Chase, Contr. U. S. Nat. Herb. 



17: 528. 1915. 



Plants perennial, gregarious ; culms erect from an ascending or decumbent base rooting at 

 the nodes, somewhat succulent, 1-2 meters high, about 5 mm. thick, glabrous, simple or occasion- 

 ally with sterile branches; nodes glabrous or the lower retrorsely appressed-pubescent; leaf- 

 sheaths usually about as long as the internodes or the upper overlapping, ciliate on the margin, 

 otherwise glabrous or pubescent on the sides at the juncture with the blade; ligule membran- 

 aceous, less than 1 mm. long; blades fiat, 20-35 cm. long, 1,5-3 cm. wide, slightly narrowed to 

 the rounded base, tapering from below the middle to an acuminate apex, sparingly pilose above 

 the ligule, otherwise glabrous, the margins scabrous; panicles 20-40 cm. long, about half as 

 wide, fusiform in outline, the main axis and rachises strongly angled, scabrous, usually sparsely 

 pilose in the lower axils, the numerous slender, compound branches rather stiffly ascending or 

 spreading, solitary or irregularly fascicled, bearing from near the base and usually along the 

 lower side rather stiffly spreading slender secondary branchlets, the lower 1-2 cm. long; spike- 

 lets loosely clustered, short-pediceled, glabrous, 1.8 mm. long, about 0.6 mm. wide, acute; 

 first glume about one third as long as the spikelet, acute, scabrous on the keeled midnerve, the 

 second glume two thirds as long as the spikelet, somewhat boat-shaped, scabrous on the keel, 

 the sterile lemma slightly exceeding the fruit, boat-shaped and scabrous on the midnerve at 

 the apex; fruit 1.6 mm. long, 0.4 mm. wide, lanceolate, scabrous at the acute apex, the lemma 

 and palea subindurated, the margins of the lemma inrolled only at the base. 



Type locality: Frijoles, Canal Zone. 

 Distribution: Southern Mexico to Panama. 

 Illustration: Contr. U. S. Nat. Herb. 17:/. 181. 



65. Panicum polygonatum Schrad.; Schultes, in R. & S. Syst. Veg. 



Mant. 2: 256. 1824. 



Panicum potamium Trin. Gram. Pan. 239. 1826. 



Panicum hydrophilum Trin.; Nees, Agrost. Bras. 208, as synonym. 1829. 



Setaria polygonata Kunth, Rev. Gram. 47. 1829. 



Panicum trichogonum Willd.; Steud. Norn. ed. 2. 2: 261, as synonym 1841. 



Panicum pilosum polygonatum Doeil, in Mart. Fl. Bras. 2 2 : 211. 1877. 



Panicum Bourgaei Fourn. Mex. PI. Gram. 25. 1886. 



Plants rather freely branching from the lower nodes, widely spreading from a decumbent 



or creeping base, rooting at the nodes; culms 20-100 cm. long, the nodes densely pubescent; 



leaf-sheaths shorter than the internodes or sometimes nearly equal, densely ciliate, otherwise 



glabrous or hirsute toward the summit; ligule less than 0.5 mm. long; blades ascending or 



spreading, oblong-lanceolate, 3-13 cm. long, 8-15 mm. wide, usually ciliate at the cordate base, 



otherwise glabrous or occasionally sparsely hirsute; panicles 7-20 cm. long, about half as wide, 



the lower branches solitary, distant, spreading, the upper sometimes in pairs, the numerous 



raceme-like branchlets secund from the lower side of the branches, the somewhat clustered, 



short-pedicled spikelets also secund on the branchlets, the rachises sparsely pilose with long, 



weak hairs, or sometimes glabrous; spikelets 1.4-1.5 mm. long, 0.5 mm. wide, not thickened, 



