220 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



fascicles subsessile, ascending or spreading; bristles united at the very b tee, unequal, 

 the outer short and slender, the inner stout, flattened and sparsely ciliate below 

 (sometimes scabrous only but with some ciliate in the same fascicle, rarely none cili- 

 ate), commonly erect or appressed with ascending tips, 5 to 8 mm. long, the inner- 

 most sometimes 15 to 25 cm. long, rarely longer, flexuous (this innermost bristle com- 

 monly elongate in the lower fascicles and not in the upper in the same panicle, but 

 sometimes elongate in all and sometimes not in any); spikelets 1 to 5 in each fascicle, 

 sessile, 5 to G mm. long, about 1.3 nun. wide, glabrous or scaberidons: glumes thin, 

 acute, the first 1-nervecl, one-third to half the length of the spikelet, the second 6 1" 

 7-nerved, two-thirds to three-fourths the length of the spikelet, or the attenuate tip 

 elongate; sterile lemma slightly shorter than the fertile one, 5 to 7-nerved, acumii 

 inclosing a palea of about equal length and usually a staminate flower: fruit suhin- 

 durate, the apex attenuate and spreading. 



In this species the fascicles vary greatly in size. Specimens with few-flowered 

 fascicles and short bristles appear distinct from those with fascicles of 4 or 5 spikelets 

 and elongate innermost bristles, but in several specimens 

 almost the entire range of variation in fascicles is found 

 from base to summit of a single panicle. The type spec- 

 imen of Cenchrus multiflorus and that of Pennisetum mul- 

 tiflorum represent about the extremes of inflorescence, the 

 first with short, relatively thick, bristles, plentifully cili- 

 ate, the second with long, Aery slender bristles, very 

 sparingly or not at all ciliate. Jimenez's no. 522 has an 

 exceptionally large panicle, the innermost bristles of all 

 fascicles elongate, a few of them 5 cm. long. 



DISTRIBUTION. 



Rocky, open, dry or moist slopes, mostly in the up- 

 lands, from Mexico to Costa Rica. 

 Sonoka: Alamos, Rose, Standley & Russell 12866. 

 Jalisco: Guadalajara, Hitchcock 7342, 7364; Hohiay 3; 



Pringle 2044, 3849, 11327. 

 Guerrero: Balsas, Hitchcock 6791. Acapulco, Palmer 75 



in 1895. 

 Oaxaca: San Agustfn, Liebmann 341. Oaxaca, Gahntti 

 5880. 

 Chiapas: Between San Ricardo and Ocozocuantla, Nelson 2895\ Ocuilapa, Kchon 

 3065. 2.C? r^T 



(Costa Rica: Nuestro Amo, Jimenez 522. 



Fig. 67.— Pennisetum hanvin- 

 skyi. From Pringle 3849, 

 Mexico. 



6. Pennisetum setosum (Swartz) L. Rich. 



Cenchrus setosus Swartz, Prodr. Veg. Ind. Occ. 26. 1788. "India occidentalis. " 

 The type specimen in the Swartz Herbarium at Stockholm was examined by A. S. 

 Hitchcock. 



Panicum cenchroides L. Rich. Act. Soc. Hist. Nat Paris 1: 106. 1792. "E Cayenna 

 missarum a Domino Le Blond. " The type has not been examined. The description 

 is insufficient for identification. The name is referred here on the authority of 

 Doell. 25 



Pennisetum setosum L. Rich, in Pers. Syn. PI. 1: 72. 1805. Based on Cenchrus 

 setosus Swartz. 



25 In Mart. Fl. Bras. 2 2 : 306. 1877. 



