15 



above the ligiile, with riiiid white hairs about 5 mm. lono;. Leaf-blades 15 to 30 

 cm. ioiig, 6 to 12 mm. wide, plane, scarcely narrowed at the al)ruptly rounded 

 and somewhat clasj)ing base, gradually tapering to a very slender, attenuate 

 and invohite, filiform apex, very sparingly tuberculate-pilose on both sides or 

 nearly smooth beneath, oiliate and scabrous on the cartilaginous margins. 

 Intiorescenoe a pale green, long-exserted, erect or very slightly curved spike, 

 solitary or 2 from the upper sheath, 9 to 12 cm. long, the spikelets in pairs, 

 one sessile and one short-pedicellate, in two rows on one side of the smooth 

 racliis. Spikelets ovate, acute, glabrous, 3 to 4 mm. long; first glume of the sessile 

 spikelet one-third as long as the flowering glume, or shorter, obtuse, hyaline, 

 not increasing in size toward the apex of the spike; that of the pedicellate spike- 

 let lateral or twisted so as to appear in a lateral position, lanceolate, acuminate, 

 about three-fourths as long as the flowering glume, 1 -nerved, scabrous at the 

 apex; second glume ovate, acute, glal)rous, 3 or faintl}' 5 nerved, equaling the 

 flowering glume in length; third glume concave, 3-nerved, slightly exceeding 

 the flowering glume, subtending a lanceolate, hyaline, 2-nerved palea as long as 

 the glume; flowering glume ovate, acute, minutely striate or pitted throughout. 

 Palea similar in texture and markings, plane or slightly concave. 



Type specimen 6717 C. G. Pringle, Valley of Oaxaca, State of Oaxaca, July 13, 1897. 



This species belongs to the group on which Fournier based his genus Dimorpho- 

 xldcJii/x,^ and is related to the South American Patiirum 'muDoainrln/tnn,'^ l)ut is 

 abundantly distinc-t, differing from the description and plate in Kunth's Rev. 

 Gram. 380, /. 104, in its larger size, smooth nodes and culms, broader and not 

 soft pilose leaves, larger spikelets, and much larger first glume of the sessile 

 spikelet; moreover Kunth does not mention or figure a long lateral first glume 

 of the pedicellate spikelet in his description of P. monodacliyum, which is so 

 prominent in our species. 



Distributed as Paspulum sdiaffneri Griseb. 



*Panicuni viscidellum Scribn. U. S. Dept. Agr. Div. Agros. Cir. 19: 2 (January, 

 1900). 



A slender, ascending or erect, finally branching perennial, 6 to 10 dm. high, with 

 numerous bearded nodes, pubescent internodes, pubescent sheaths, lanceolate, 

 acute, pubescent leaves, and ovate, exserted panicles 5 to 7 cm. long. Leaves 

 5 to 8 cm. long, 1 to 2 cm. broad, cordate-clasping at the base; ligule pilose. 

 Panicle branches somewhat viscid, the lower ones 2.5 to 3 cm. long. Spikelets 

 1.8 mm. long, obovate, obtuse, or subacute, the 7-nerved second and third glumes 

 glabrous or with a few scattering hairs. 



Gravelly banks near Jalapa, State of Vera Cruz, altitude 1,250 m., 8089 C. G. Prin- 

 gle, October, 1899; same locality, 1617 C. L. Smith, 1894; in thickets near Mira- 

 dor, 323 Liebmann, 1841. 



Related to Panicum scoparium Lam. (P. viscidnm. Ell. ), but stems much more slender, 

 leaves shorter and less rigid, panicles smaller, as are also the spikelets, which 

 are nearly smooth. Fournier, in his enumeration of the grasses of Mexico, 

 refers this grass to P. cowmeUncTfolium Rudge,^ and cites P. iiu(li{tlorum Ell. and 

 P. microcarpon "Michx." as synonyms. I have not Rudge's work, " Plantee 

 Guiana;," in which P. commelmsefol'mm is illustrated, and upon which illustration 

 Fournier based his determination of Liebmann's plant, but our grass is certainly 

 not P. iimltiflorum Ell. (P. pohjavthes Schultes), nor does it agree with available 

 descriptions of P. commelunefoUwn. P. microcarpon Ell., Sk. Bot. S. C. and Ga. 

 127, 1817, not Muhl., is the grass now usually referred to P. harbulatum Mx. 



iMex. PL 2: 13 (1881). 



^H. B. K. Nov. Gen. et Sp. PI. 1: 96 (1815). 



»Mex. PI. 2: 20 (1881). 



