76 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



panicles rather long-exserted, those of the branches short-exserted or slightly included 

 at base, 7 to 20 cm. long, usually scarcely half as wide, the flexuous branches ascending, 

 bearing short, rather spreading branchlets with 1 to 3 spikelets toward their ends, the 

 whole forming a more evenly flowered panicle than in P. hallii; spikelets 4 to 4.2 mm. 



long, about 1.5 mm. wide, narrowly ovate, 

 turgid, acuminate; first glume about half 

 the length of the spikelet, acuminate, 5- 

 nerved, the midnerve scabrous toward the 

 apex; second glume and sterile lemma 

 strongly 7 to 9-nerved, the midnerves scab- 

 rous toward the apex; fruit 2.3 to 2.5 mm. 

 long, 1.3 to 1.5 mm. wide, oval, turgid, 

 obtuse. 



Type TJ. S. National Herbarium no. 

 155163, collected September 22, 1885, by 

 streams, rocky hills near Chihuahua, State 

 of Chihuahua, Mexico, by C. G. Pringle 

 (no. 497), and distributed as P. diffusum 

 Swartz. 

 This species is distinguished from P. 

 hallii by the more evenly flowered, narrower panicle of larger spikelets, and by the 

 greater amount of pubescence. The plants average taller than P. hallii, though Pal- 

 mer 533 is a depauperate specimen only 15 cm. high. 



A specimen from Santa Catalina Mountains, Arizona, Griffiths 7063, with spikelets 

 only 3.8 mm. long, is doubtfully referred here. 



Fig. 64,— P. lepidulum. From type specimen. 



DISTRIBUTION. 



Moist places in the mountains, Chihuahua to the City of Mexico. 

 Mexico: Chihuahua, Pringle 497; Durango, Palmer 525 in 1896, 533 in 1906; City 

 of Mexico, Hitchcock 5958. 



37. Panicum ghiesbreghtii Fourn. 



Panicum ghiesbreghtii Fourn. Mex. PI. 2 : 29. 1886. This name was earlier listed 

 by Hemsley a without description. Fournier cites three specimens, the first being 

 ''Absque loco (Ghiesbreght)," which, since the species is named for this collector, 

 is taken as the type. This is in the Paris Herbarium. It was collected in Mexico in 

 1845. A specimen collected by Ghiesbreght in Mexico 

 and labeled P. ghiesbreghtii in the herbarium of the 

 Botanical Garden in St. Petersburg, is P.fili'pes. 



Panicum hirtivaginum Hitchc. Contr. Nat. Herb. 12 : 

 223. 1909. "Type specimen Wright 758, Cuba, U. S. 

 National Herbarium no. 559958." The label on this 

 specimen gives no locality in Cuba. 



description. 



Plants in small tufts, rather robust; culms erect, pa- 

 pillose, ascending-hirsute, 60 to 80 cm. high, the nodes 

 densely hirsute ; sheaths mostly longer than the inter- 

 nodes, hirsute like the culms; ligules about 2 mm. 

 long; blades erect or ascending, as much as 60 cm. 



long and 12 mm. wide, flat, not narrowed to the rounded base, papillose-hirsute 

 on both surfaces or glabrescent; panicle short-exserted, nearly equaled by the 



Fig. G5. 



-P. ghiesbreghtii. From 

 type specimen. 



a Biol. Centr. Amer. Bot. 3 : 489. 1885. 



