84 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Fig. 74.— Distribution of P. bulbosum sciaphilum. 



DESCRIPTION. 



Plants less than 1 meter, sometimes only 30 to 40 cm. high; culms slender, few to 

 many in loose clusters, the corms smaller, not over 8 mm. in diameter, commonly 

 many together attached at the base to a rootstock; blades 10 to 40 cm., usually less 

 than 25 cm. long, 2 to 4 mm. wide; spikelets 2.8 to 3.2 mm. long. 



As limited here this subspecies includes only those specimens having both the 

 smaller spikelets and narrower blades. Many intergrading forms are included in the 

 species. 



DISTRIBUTION. 



Gravelly river banks, ravines of mesas and similar situations in the Rocky and 

 Sierra Madre mountains from New Mexico and Arizona to central Mexico. 



New Mexico: Mangas, Smith in 1897; Las Vegas, Vasey in 1881; Mogollon Moun- 

 tains, Metcalfe 357; Gray, Earle & Earle 180; Organ Mountains, Hitchcock 



3784; Niggerhead Mountains 



near Monument no. 82, Mearns 



1932; without locality, Wright 



2086. 

 Arizona: Chiricahui Mountains, 



Tourney 12; Santa Rita Moun- 

 tains, Pringle in 1884; San 



Francisco Mountains Forest 



Reserve, Leiberg 5816; Burro 



Mountains, Rusby 445c in part; 



Yavapai County, Rusby in 



1883; Flagstaff, Jones 4019; 



Patagonia, Hitchcock 3716; 



Huachuca Mountains, Griffiths 4811, Holzner 1729, 1742, Lemmon 2908, 2922; 



Fort Huachuca, Wilcox in 1891; Bill Williams Mountain, Lemmon 3152; 



Beaver Creek, Rusby 866; without locality, Rothrock 296. 

 Mexico: Nogales, Griffiths 6785|; Chihuahua, Nelson 6298; Cusihuiriachic, Pringle 



1406; Otinapa, Palmer 348, 349, and 554 in 1906; Tejamen, Palmer 469 in 



1906 in part; Papasquiaro, Palmer 467 in 1896; Territorio de Tepic, Rose 2053. 



Virgata. — Perennials from stout rootstocks; mostly maritime species, with stout 

 simple culms and firm foliage; ligules membranaceous, ciliate; panicles open 

 or contracted; spikelets glabrous, mostly large, terete or thicker than wide, 

 usually gaping, owing to the well-developed staminate floret and its palea 

 in addition to the perfect one, the glumes and sterile lemma firm in texture, 

 the fruit relatively rather small, smooth and shining, in some species the 

 margins of the lemma scarcely inrolled. 

 Spikelets not over 2.5 mm. long, first glume less than half the 

 length of the spikelet. 

 • Panicles loosely flowered; first glume truncate, about 



one-fifth the length of the spikelet . 42. P. repens. 



Panicles rather densely flowered; first glume triangular, 



about one- third the length of the spikelet 43. P. gouini. 



Spikelets 3 to 7 mm. long (sometimes less than 3 mm. in P. 

 virgatum cubense); first glume more than half the length 

 of the spikelet. 

 Panicles elongated, strongly contracted; seacoast plants. 

 Culms rarely 1 meter high, solitary from the nodes of 

 the horizontal rootstock . 



46. 



Culms 1 to 2 meters high, in dense tufts. 47. 



P. amarum. 

 P, amarul'um. 



