132 PANICACE^. 



Arizona, PruujJe. 



Var. avenaceum (H. B. K.). P. avenaceufn H. B. K. Nov. 

 Gen. et Sp. 1 : 99 (1815). Spikelets subsessile, about 3 mm. long, 

 often purple ; first glume scarcely half as long as the spikelet, the 

 lower floret often staminate, fertile floret 3 mm. long. 



Mexico, Pringle 377. 



Arizona, Mexico, Quito, Guyana. 



48. P. MAXIMUM Jacq. Ic. PI. Rar. Coll. 1: t. 13, 76 (1786). 

 Guinea. Gkass. P. jumentornin Vers. Syn. 1:83 (1805). 



A stout perennial, from scaly, creeping rootstocks. Culms 

 smooth. 80-150 cm. high, nodes smooth or silky hairy. Leaf- 

 blades smooth, 20-30 cm. long, 5-10 mm. wide; ciliate at the 

 ligule and on the margins of the smooth sheath. Panicle large, 

 15-20 cm. or more long, erect, the numerous rays erect or spread- 

 ing, bearing spikelets above the middle of the main branches. 

 Spikelets on pedicels, usually 1-5 mm. long, smooth, elliptical or 

 oval, acute, 4 mm. long; first glume ovate, rounded, acuminate, 

 7-nerved, 3-4 mm. long; second glume and floral glume of the 

 staminate floret broad-ovate, 3-7-nerved, the latter a little the 

 shorter; palea ovate, as long as its glume. Stamens 3. Fertile 

 floret smooth, transversely wrinkled, 2.5-3 mm. long. 



Cultivated in the warmer States; also found in Mexico, West 

 Indies, Buenos Ayres. Introduced from tropical Africa. 



This must not be confounded with Sorghum halejjense, often 

 called Johnson Grass. 



49. P. Hallii Vasey, Bull. Torr. Club, 11:61 (1884). 



Culms caespitose, slender, erect, smooth, branching below, 

 30-60 cm. high. Ligule a ciliate ring; sheaths smootli or 

 pubescent; blades flat, nearly smooth, light green, about 4 to 

 each culm, 8-15 cm. long, 3-15 mm. wide. Panicle exserted or 

 the lower partially included, 8-15 cm. long, simple, spreading; 

 rays mostly single, naked below and few-flowered. Spikelets very 

 smooth, pale green or purple, single or in pairs, mostly borne 

 above the middle of the branches, lanceolate-ovate, acute, 3-4 mm. 

 long; first glume acute or obtuse, one-third to one-half as long as 

 the spikelet, 5-nerved; second glume ovate-lanceolate, acute, 



