HITCHCOCK AND CHASE NORTH AMERICAN PANICUM. 



139 



80. Panicum rudgei Roem. & Schult." 



Bras. 48. 1823. "Species rarissima 



Panicum scoparkim Rudge, PL Guian. 1 :21. pi. 29. 1805, not Lam. 1798. No-par- 

 ticular locality in Guiana is mentioned by Rudge. In the Berlin Herbarium is a 

 specimen from Rudge which is authentic though it probably is not the type. The 

 original description and the plate leave no doubt as to the identity of the species. , 



Panicum rudgei Roem. & Schult. Syst. Veg. 2: 444. 1817. Based on "Pan. 

 scoparium Rudge. " 



Panicum rudgei brasiliense Raddi, Agrost. 

 observata tantum in viciniis fluminis Inhu- 

 mirim.' ' We have not seen the type of this, 

 but the description applies to the type of P. 

 rudgei. 



Panicum dasytrichum Spreng. Syst. Veg. 

 1: 317. 1825. "Brasil." The type, in the 

 Sprengel Herbarium, was collected by Hoff- 

 mansegg. 



Panicum hirsutum Willd.; Spreng. Syst. 

 Veg. 1: 317. 1825, not Swartz, 1797. This 

 is given as a synonym under P. dasytrichum 

 and is credited to "W. herb." The type, 

 in the Willdenow Herbarium, was collected 

 by Hoffmansegg in Brazil. 



Panicum rhigiophyllum Steud. Syn. PL 

 Glum. 1: 76.1854. "P.rigens. Salzm. Hrbr. Bahia. " This specimen was not found 

 in the Steudel Herbarium, but a Salzmann specimen bearing this name was examined 

 at Halle. 



Fig. 133.— P. rudgei. From Salzmann's 

 specimen of P. rigens. 



a The following species, though not North American, may here be described on 

 account of its relationship to Panicum rudgei: 



Panicum rotundum sp. nov. 



Plants perennial, in small tufts; culms 30 to 50 cm. high, rather stout, stiff, erect or 

 somewhat geniculate at base, densely ascending-hirsute, the nodes densely bearded ; 

 sheaths, except the upper, mostly shorter than the internodes, hirsute like the culms; 

 ligules membranaceous, ciliate, the hairs mingling with those of the blade ; blades thick, 

 erect or appressed, linear, 5 to 20 cm. long, 2 to 5 mm. wide, more or less involute, at 

 least toward the long-acuminate apex, only as wide as the sheath at base, the juncture 



obscure, densely hirsute on the upper surface, 

 harshly velvety beneath; panicles terminal and in 

 the axils of the upper 1 to 3 leaves, forming an oblong 

 inflorescence as in P. rudgei, about one-third the 

 height of the plant, the main axis pilose, the slender, 

 angled, scabrous, stiff but flexuous branchlets as- 

 cending or spreading, pilose in the axils, the long 

 pedicels divergent; spikelets2.3 to 2.5 mm. long, 1 

 to 1.2 mm. wide, very turgid, abruptly pointed, 

 strongly nerved, a few stiff, appressed hairs here 

 and there between the nerves; .first glume over half 

 the length of the spikelet, abruptly pointed; sec- 

 ond glume and sterile lemma subequal, exceeding the fruit, the lemma subtending 

 a palea and staminate flower; fruit 1.8 mm. long, 1 mm. wide, ellipsoid, smooth and 

 shining, a broad scar at the base. 



Fig. 134.— P. rotundum. From 

 type specimen. 



