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 Scop ARIA, 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 Lanuginosa, 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 sui'face 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. 



Jloist banks and rich woods, southeastern United States to Guatemala; also Santo 

 Domingo. The type specimen from Jalapa. 



Hidalgo: Trinidad Iron Works, 



Pringle 13250. 

 PuEBLA : Chinantla, Liebmann 



328. 

 Veracruz: Jalapa, Pringle 8083, 



Hitchcock 6587, Amer. Gr. 



Nat. Herb. 84, Smith 1752. 



C6rdoba, Bourgeau 2162. 



Boca del Monte, Nelson 201, 



Seler 2160. 

 Guatemala: CobAn, Turckheim 



0831. 

 Santo Domingo: Constanza, Tilrckheim 3059 



Eggers 2129. 



tf^ 



v4_^j '-iv/*j.Ty "^ 





-^ 



\ A V\ J'^-^^^^^yx ^^ 









'i 





/^Wv { 





Fig. 104. — Distribution of P. xalapense. 



Rio Yaqui near Jarabacoa, 



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 



