THE NORTH AMERICAN SPECIES OF PENNISETUM. 



231 



scabrous; fascicles on minute pubescent peduncles, ascending; bristles slender, scant 

 (mostly less than 20), unequal, most of them shorter than the spikelet or but little 

 exceeding it, the innermost about twice as long as the spikelet; spikelets 4.5 to 5.5 

 mm. long, 1 to 1.2 mm. wide, acuminate; glumes unequal, obscurely ciliolate, the 

 first minute, J -nerved, acute or obtuse, the second about one-third to nearly half the 

 length of the spikelet, 3-nerved, acute or subacute; sterile lemma slightly exceeding 

 the fertile lemma. 5-nerved, depressed down the middle, scabrous, especially toward 

 the summit, acuminate, the palea wanting; fruit acuminate, but little indurate, the 

 lemma 5-nerved and scabrous toward the summit, the margins thin and flat. 



This species is very closely related to Penniseturn latifolium Spreng. of the Atlantic 

 slope of South America from Bradl to Uruguay. That, like P. distachyum, has been 

 referred to P. tristachyvm. The illustration given by Doell. 15 as Gymnothrix trisfachya 

 H. B. K. represents P. latifolium. In that species, described from Montevideo, the 

 blades are on the average longer for their width than in P. distachyum, the panicles 

 are mostly longer and yellowish, and the bristles longer, the innermost one three to 

 four times the length of the spikelet. 



DISTKIBUTION. 



In moist ground, in ravines and along stream borders and irrigation ditches, in the 

 uplands from southern Mexico to Costa Rica. 

 Veracruz: Zacuapan, Pur-pus 2894. Mirador, Liebmann 339. Orizaba, Boiteri 96, 



631, 1209, 1214 in part; Bourgeau 2543; Milller 2066; Seaton 291. Cordoba, Bour- 



geau 1664. 

 Oaxaca: Cuicatlan, Pringle 5558, 5559. 

 Guatemala: BajaVerapaz, Tilrckheim 3880. 

 Costa Rica: San Francisco de Guadalupe, Jimenez 2; Tonduz 8020, 14064. San 



Jose\ Hitchcock 8448. San Ram6n, Tonduz 17910. . 



13. Penniseturn prolificum Chase, sp. nov. ' 



Plants perennial; culms 2 to 4 meters tall (probably taller, the base not seen), 

 very robust, glabrous, branching from the upper nodes, the branches often in fascicles 

 of 2 to several, relatively slender, repeatedly 

 fasciculately branching, the ultimate branchlets 

 very slender, nodding, their nodes often strongly 

 geniculate, the very numerous panicles 2 to 5 

 together on very slender, fiexuous, usually gla- 

 brous peduncl s, mostly 2 to 10 cm. long, the 

 terminal panicle often solitary, the whole system 

 of branches forming a great drooping leafy com- 

 pound tawny inflorescence often 1 meter or more 

 long and probably nearly as wide; nodes gla- 

 brous or strigose; sheaths loose, glabrous or cili- 

 ate on the margin above, sometimes with a few 

 long soft hairs at the summit; ligule stiff, lacerate- 

 ciliate, about 2 mm. long; blades flat, "mostly 

 spreading, 15 to 50 cm. long, 2 to 4 cm. wide (on 

 the average a little shorter and broader than those 

 of P. distachyum), narrowed but not long-attenuate 

 at base, glabrous on both surfaces or slightly 

 scabrous above, those of the branches progressively smaller, the ultimate ones 

 much more reduced than those of P. distachyum; peduncles unequal, one panicle 

 of a fascicle partly included; panicles tawny, 3 to 5 cm. long, about 1 cm. wide, 



Fig. 75. 



Penniseturn prolificum. From 

 type specimen. 



45 In Mart. Fl. Bras. 2 2 : pi. 41. 1877. 



