’ 
HITCHCOCK AND CHASE—TROPICAL .NORTH AMERICAN PANICUM. 513 
Spikelets not attenuate at base. 
Culms tall, usually 75 cm. high 
or more; foliage velvety- 
pubescent .........-.-.. See Scoparta, p. 523. 
Culms not over 50 cm. high. 
Spikelets not over 1.3 mm. 
long; sheaths and 
culms appressed-pu- 
bescent ............ See Spreta, p. 518. 
Spikelets 1.7 to 2.4 mm. 
long; plants conspic- 
uously pubescent, at 
least on the sheaths. See Lanuainosa, p. 519. 
LAXIFLORA. 
Spikelets papillose-pilose; sheaths retrorsely pilose. ............. 78. P. xalapense. 
Spikelets glabrous; sheaths not retrorsely pilose. 
Blades glabrous on the surface. ............-...-.---------- 79. P. polycaulon. 
Blades pilose on the surface............-.-2--2-+2--2----+---- 80. P. strigosum. 
78. Panicum xalapense H. B. K. 
Panicum xalapense H. B. K. Nov. Gen. & Sp. 1: 103. 1816; Contr. U. S. Nat. Herb. 
15: 159. 1910. 
DISTRIBUTION. 
Moist banks and rich woods, southeastern United States to Guatemala; also Santo 
Domingo. The type specimen from Jalapa. 
Hipateo: Trinidad Iron Works, 
Pringle 13250. 
Puesia: Chinantla, Lvebmann 
328. 
Veracruz: Jalapa, Pringle 8083, 
Hitchcock 6587, Amer. Gr. 
Nat. Herb. 84, Smith 1752. 
Cérdoba, Bourgeau 2162. 
Boca del Monte, Nelson 201, 
Seler 2160. 
GUATEMALA: Cobén, Tiirckheim Fia. 104.—Distribution of P. ralapense. 
3831. ‘ 
Santo Dominco: Constanza, Tiirckheim 3059. Rio Yaqui near Jarabacoa, 
Eggers 2129. 
79. Panicum polycaulon Nash. 
Panicum dichotomum §£ glabrescens Griseb. Fl. Brit. W. Ind. 553. 1864. ‘‘Pd. 
[Purdie], in mountain-savannahs [Jamaica].’’ The type specimen is in the Kew 
Herbarium. 
Panicum polycaulon Nash, Bull. Torrey Club 24: 200. 1897; Contr. U. S. Nat. Herb. 
15: 163. 1910. 
82472°—15——_5 
