326 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



The name P. latifolium L. has been applied to this species by some authors but 

 the type of the former belongs to a very different species. a 



DESCRIPTION. 



Plants perennial, decumbent at base, rooting and rather sparingly branching at 

 the lower nodes; culms spreading or ascending, 0.5 to 1 meter long beyond the decum- 

 bent base, rather robust, more or less angled, glabrous, rarely with a few appressed 

 hairs below the glabrous nodes; sheaths densely short-ciliate, otherwise glabrous or 

 papillose-hirsute toward the summit; ligule nearly obsolete; blades 4 to 15 cm. long, 

 8 to 30 mm. wide, cordate-clasping, acuminate, glabrous or rarely with a few 

 appressed hairs; panicles short-exserted, 10 to 25 cm. long, composed of a few ascend- 

 ing or appressed, stiff, slender 

 branches 3 to 10 cm. long, 

 bearing throughout their length 

 short, appressed branchlets with 

 more or less secund spikelets, 

 mostly two on each branchlet, 

 one nearly sessile, the other on 

 a pedicel about as long as the 

 spikelet, the branchlets angled, 

 scabrous; spikelets 5.5 to 6 mm. 

 long, 2 to 2.5 mm. wide, and as 

 thick or thicker, obovoid, ab- 

 ruptly short-pointed, glabrous; 

 first .glume about two-thirds 

 the length of the spikelet, acute, 

 3 to 5-nerved, second glume and 

 sterile lemma equal, abruptly 

 contracted into a short, keeled 

 tip, 5-nerved, the lateral nerves 

 of the lemma usually obsolete 

 below the summit, the sterile 

 palea about two-thirds as long as its lemma; fruit 4.7 to 5 mm. long, 1.8 to 2 mm. 

 wide, becoming dark brown at maturitj', smooth and shining, the lemma somewhat 

 boat-shaped and with a short erose, laterally compressed crest at the apex, the apex 

 of the palea similarly compressed and bent outward. 



Closely related to P. zizanioides is Panicum paucispicatum Morong b from Paraguay, 

 which is distinguished from this by the smaller panicles, pubescent spikelets, and a 

 more pronounced crest to the fertile lemma. 



Fig. 367.— p. zizanioides. From specimen in Bonpland 

 ^ Herbarium. 



DISTRIBUTION. 



Woods and copses, Mexico, West Indies, and south to Paraguay. 

 Mexico: Ocuilopa, Nelson 3023; Trapiche de la Concepcion, Liebmann 394; San 



Juan Bautista, Rovirosa 624. 

 Guatemala: Dept. Alta Vera Paz, Tuerchheim 7699, 7700, 8785, 8796. 

 Costa Rica: La Florida, Pittier 11276; Talamanca, Tonduz 8566; San Rafael, 

 Pittier 2598. 



a For a further discussion see Hitchcock, Contr. Nat. Herb. 12 : 118. 1908. One of 

 the sheets upon which Linnaeus has written the name "latifolium" is P. zizanioides. 

 But this was received from Browne in Jamaica after the publication of the first edition 

 of Linnaeus's Species Plantarum and hence could not be the type of P. latifolium. 



b Ann. N. Y. Acad. Sci. 7 : 262. 1893. 



