THE NORTH AMERICAN SPECIES OF PENNISETUM. 



229 



Chihuahua. Since no. 498 is erroneously cited as 489, the second specimen cited. 

 Pringle's no. 817, is taken as the type. This is a single complete culm 1.5 meters tall. 



Pcnnisetum crinitum Scribn. ; Beal, Grasses N. Amer. 2: 163. 1896. Not Pennisetum 

 crinitum Spreng. 1825. A herbarium name gh r en as synonym of P. durum. 



Pennisetum pringlei Leeke, Zeitschr. Naturw. 79: 33. 1907. "Mexiko." The 

 detailed description identifies the species. No specimen is cited, but from the 

 specific name it is to be supposed that the description was drawn from one of Pringle's 

 three collections of this species, his numbers 498, 817, or 4962. 



DESCRIPTION. 



Plants perennial; culms few to several from a hard knotted crown, erect, mostly 

 rather robust and rigid, 1.2 to 2 meters tall, usually glaucous, strigose or scabrous 

 on the nodes and just below them, otherwise glabrous, slightly compressed, simple 

 or rarely with a few leafy branches from the upper nodes; sheaths loose, mostly 

 much shorter than the internodes, pubescent on the 

 margin toward the summit and usually on the collar, 

 otherwise glabrous or rarely scaberulous, the scarious 

 margin (especially in the large lower leaves) sometimes 

 produced into an erect auricle at the summit; ligule a 

 ring of stiff hairs 1.5 to 2 mm. long; blades ascending 

 or spreading, mostly rather firm, scabrous and sparsely 

 pilose on both surfaces, or smooth or glabrous beneath, 

 rarely also on the upper surface, 15 to 60 cm. long, 5 to 17 

 mm. wide, narrowed to the base (often in the lower leaves 

 almost petiole-like) and tapering into a long involute- 

 setaceous scabrous tip; panicles terminal and on slender 

 naked peduncles exserted from the upper 2 to 4 sheaths, 

 1 to 4 peduncles from a sheath, the panicles nodding, 

 3 to 10 cm. (rarely 11 to 12 cm.) long, mostly 8 to 10 

 mm. thick, usually pale, the axis very slender, angled 

 and scabrous; fascicles sessile, ascending; bristles rather 

 scant, unequal, most of them shorter than the spikelet, 

 the innermost longer, sometimes twice the length of the 

 spikelet; spikelet solitary, sessile, 6 to 7 mm. long, 

 about 1.5 mm. wide, acuminate, glabrous; glumes 1 

 to 3-nerved, acutish, the first about one-third and the 

 second half the length of the spikelet; sterile lemma 

 equaling the fruit or slightly shorter, 5-nerved, acute, 

 its palea obsolete; fruit subindurate, acuminate. 



Fig. 7: 



73 . — Pennisetum durum. 

 From type collection. 



DISTRIBUTION. 



On dry rocky slopes in the highlands of Mexico; apparently rare. 

 Chihuahua: Santa Eulalia Mountains, Pringle 498. Potrero Mountains, Pringle 817. 

 Oaxaca: Sierra de San Felipe, Pringle 4962; Conzatti & Gonzdlez 491. 



12. Pennisetum distachyum (Fourn.) Rupr. 



Pennisetum distachyum Rupr. Bull. Acad. Sci. Brux. 9 2 : 242. 1842. "(Sectio Gym- 

 nothrix. Beauv.) (Coll. H. Galfeotti]. no. 5680.) [Perennial].— Cette espece remar- 

 quable et qui atteint la taille elevee de 15 a. 16 pieds, cr6it par grosses touffes, comme 

 les Bambusae, dans les ravins sombres et humides de la Barranca de San Martin, pies 

 de Zacuapan (Etat de Vera-Cruz), a, 1,500 pieds de hauteur absolue." No further 

 description is given. The name is given by Founder as a synonym of Gymnothrix 

 distachya Fourn. 



