HITCHCOCK AND CHASE NORTH AMERICAN PANICUM. 



67 



27. Panicum stramineum sp. nov. 



DESCRIPTION. 



Plants ascending or widely spreading, sparingly branching at the base and lower 

 nodes, or simple, 20 to 50 cm. high; culms glabrous, the nodes appressed- villous; 



sheaths glabrous, sparsely papillose or 

 papillose-hispid ; blades erect or ascending, 

 10 to 30 cm. long, 4 to 15 mm. wide, 

 rounded or somewhat cordate at base, 

 glabrous, scabrous on the margin and 

 sometimes on the upper surface, some- 

 times ciliate at base; panicles finally ex- 

 serted, one-fourth to one-third the entire 

 height of the plant, ov6id in outline, 

 rather many-flowered, the pedicels scarcely 

 as appressed as in P. hirticaule; spikelets 

 3.2 to 3.7 mm. long, 1.5 mm. wide, elliptic, 

 abruptly acuminate, turgid, pale stramine- 

 of the spikelet, blunt or subacute, the 

 nerves usually anastomosing; second glume and sterile lemma equal, or the glume 

 slightly shorter, not much exceeding the fruit, the palea of the sterile floret as long as 

 the fruit, 2-nerved; fruit 2.2 mm. long, 1.3 mm. wide, obovate-elliptic, turgid, a rather 

 prominent scar on either side at base. 



Type U. S. National Herbarium no. 592753, collected 1887, Guaymas, Sonora, Mex- 

 ico, by Dr. Edward Palmer (no. 206). 

 This species differs from P. hirti- 

 caule in being nearly glabrous through- 

 out, in the longer blades, more turgid, 

 less long-pointed spikelets with shorter, 

 scarcely acute first glume. 



Fig. 50. — P. stramineum. From type specimen, 

 us; first glume one-third the length 



DISTRIBUTION. 



Rich bottom lands and damp soil, 

 southern Arizona and northwestern 

 Mexico. 



Arizona : Near the Mexican boun- 

 dary, Pringle in 1884; Tucson, Thornberin 1901, and 219 (the latter in N. M. 

 Agr. Col. Herb.). 

 Mexico: Guaymas, Palmer 168a and 206 in 1887; Culiacan, Palmer 1538 in 1891; 

 State of Sinaloa, Rose 1878, 1883; Acaponeta, Rose 1889, 3281. 



Fig. 51. — Distribution of P. stramineum. 



28. Panicum sonorum Beal. 



Panicum capillare miliaceum Yasey, Contr. Nat. Herb. 1 : 28 1890, not P. miliaceum 

 L. 1753. Collected at Lerdo, Mexico, at the head of the Gulf of California, in 1889, 

 Palmer 947. This is not based on P. miliaceum L. The type is in the National Her- 

 barium. 



Panicum sonorum Beal, Grasses N. Amer. 2 : 130. 1896. Based on P. capillare milia- 

 ceum Vasey. 



