226 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



heim (no. 428). It consists of four plants with mature primary panicles and freely 

 branching culms. * 



This species is closely allied to P. acuminatum, differing in the olivaceous color, the 

 less velvety pubescence, the stiff, appressed blades, and the larger spikelets. The 

 autumnal form is bushy, the branches evenly distributed, not gathered into distinct 

 fascicles as in P. acuminatum. 



DISTRIBUTION. 



Gravelly banks and cultivated fields, Mexico to Costa Rica; also in Venezuela. 

 Mexico: Jalapa, Pringle 8339 in part« (Nat. Herb. no. 823271); Orizaba, Bour- 



geau 2383 in part, Botteri 99, 101 (both in Brit. Mus. Herb.), 1987 (Paris Herb.); 



Minatitlan, J". 67. Smith 571 (Hitchcock Herb.). 

 Guatemala: Coban, Tuerckheim 428 in 1879, 428 in 1888; Seler 3235 (Berlin 



Herb.). 

 Costa Rica: San Pedro de la Calabaza, Tonduz 10745 in part (Nat. Herb. no. 



385918); Tablazo, Tonduz 7944. 

 Venezuela :-Tovar, Fendler 1638/3. 

 Colombia: Popayan, Lehmann 974 (Gray Herb.). 



131. Panicum praecocius Hitchc. & Chase. 



Panicum praecocius Hitchc. & Chase, Rhodora 8 : 206. 1906. "Type V. H. Chase 

 649; dry bank, near Wady Petra, Stark County, Illinois, June 30, 1900, collected by 

 Virginius H. Chase." The type, in the National Herbarium, is a clump of branching 

 culms, with mature secondary panicles, the primary ones being devoid of spikelets. 



description. 



Vernal culms tufted, 15 to 25 cm. high, early branching and elongating, sometimes 

 to 30 or 45 cm., at first erect, soon becoming geniculate and spreading, very slender, 

 wiry, abundantly papillose-pilose with weak spreading hairs 3 to 4 mm. long; sheaths, 

 even the lowest, much shorter than the very long internodes, those of the branches 

 usually but 1 to 2 cm. long, pilose like the culm, more prominently papillose; ligules 

 3 to 4 mm. long; blades rather firm, erect or ascending, 5 to 9 cm. long, 4 to 6 mm. 

 wide, the margins parallel about two-thirds their length, acuminate, long-pilose on 



both surfaces, the hairs of the upper surface 4 to 

 5 mm. long, erect from the plane of the blade, 

 the under surface prominently papillose; panicles 

 at first usually overtopped by the upper leaf, 

 but at or past maturity exserted, 4 to 6 cm. long, 

 about as wide, loosely flowered, the axis pilose, 

 the branches flexuous, spreading or ascending; 

 Fig. 235.-P. praecocius. From spikelets 1.8 to 1.9 mm. long, 1 mm. wide, obo- 



type specimen. vate, turgid, obtuse, pilose; first glume one-third 



to half the length of the spikelet, triangular; sec- 

 ond glume and sterile lemma subequal, the glume slightly shorter than the fruit at 

 maturity; fruit 1.6 mm. long, 1 mm. wide, broad-elliptic. 



Autumnal form ascending from a geniculate base, or in prairie sod erect, forming 

 close bunches 10 to 20 cm. high, the upper portion of the primary culms early decidu- 

 ous, the branches appressed, the scarcely reduced blades erect or narrowly ascending, 

 much exceeding the reduced panicles; winter rosette appearing late, the blades 2 to 

 3 cm. long, long-pilose. 



This species scarcely has a simple state, the branches appearing often before the 

 first panicle is expanded. 



a See footnote under P. multirameum, page 185. 



