HITCHCOCK AND CHASE NORTH AMERICAN PANICUM. 141 



81. Panicum megiston Schult. 



Panicum altissiraum Meyer, Prim. Fl. Esseq. 63. 1818, not DC. 1817. a "In sylvis 

 humidis plantationis Hofvan Holland, ' ' Essequebo or British Guiana. We have seen a 

 portion of the type in the Trinius Herbarium. The type is in the Gottingen 

 Herbarium. 



Panicum megiston Schult. Mant. 2 : 248. 1824. Based on P. altissimum Meyer. 



Panicum tuberculatum Presl, Rel. Haenk. 1 : 307. 1830. The locality given by 

 Presl is, il Hab. in Luzonia." The type, in the herbarium of the German University 

 at Prague, is labeled "Luzonia," but it probably came from Mexico. 



Panicum elatior[us] Kunth, Rev. Gram. 1: 38. 1829. Based on P. altissimum Meyer. 



Panicum equisetum Nees; Doell in Mart. Fl. Bras. 2 2 :206. 1877. This is given 

 as a synonym under P. megiston Schult., and is credited to " Nees ab Esenbeck in herb. 

 Reg. Berolinensis schedula. ,J The type, in the Berlin Herbarium, was collected by 

 Sello in Bahia, Brazil. » 



DESCRIPTION. 



Plants perennial; culms tall and robust, glabrous; sheaths papillose-hispid or 

 papillose only; ligules fimbriate, about 1.5 mm. long; blades firm, ascending, 15 to 

 40 cm. or more long, 1.5 to 3 cm. wide, linear-lanceolate, slightly narrowed to the 

 rounded base, glabrous; panicles finally exserted, 40 to 60 cm. long, the stiff main 

 axis striate-angled, smooth or scabrous, the branches in distant verticils, often as many 



as 20 to 30 in a verticil, 10 to 20 cm. long, slender, 

 stiffly or sinuously ascending, very scabrous, nearly 

 simple, bearing the scattered, short-pediceled spike- 

 lets along the upper half or third; spikelets usually 

 purplish at maturity, about 3.4 mm. long, 1.5 mm. 

 wide, globular-obovoid, glabrous; first glume scarcely 

 one-third the length of the spikelet, pointed; second 

 glume slightly shorter than the sterile lemma, both 

 abruptly apiculate, 7 to 9-nerved, the glume about 

 equaling the fruit, the sterile palea rather firm, about 

 as long as the fruit; fruit 2.8 mm. long, 1.4 mm. wide, 

 abruptly pointed, smooth and shining. 



Fig. 135.-P. megiston. From type Me y er stateS that the Culms asCend to a hei g ht of 20 

 specimen of P. altissimum Meyer. or 30 feet and that they are much branched. Our 



specimens are all, with the exception of Wright 3872, 

 the simple upper part of the culm only. Eggers, on the label accompanying his 

 no. 14345, gives the height as 6 to 8 feet. The Wright specimen, except for the 

 underground portion, is entire. This is simple and measures but 1.2 meters in height. 

 This species somewhat resembles P. oaxacense and P. procerrimum of the genus 

 Lasiacis, but the fruit has not the form and texture characteristic of that genus. 



DISTRIBUTION. 



In moist woods, Mexico and Cuba to Paraguay. 

 Mexico: San Juan Bautista, Rovirosa 532. 

 Cuba: St. Cruz de los Pinos, Wright 3872. 

 Venezuela: Santa Catalina, Rusby & Squires 355. 

 Brazil: Without locality, Riedel 1239, Gardner 1179. 

 Paraguay: Morong 813, 1072. 

 Ecuador: Balao, Eggers 14345. 



a Poem. & Schult. Syst. Veg. 2: 457. 1817. The diagnosis is here referred to 

 De Candolle " Hornem. Hort. Eafn. I. p. 84." The latter work we have not seen, nor 

 that cited by the Index Kewensis, "Elench. Hort. Monsp. 42. 1805," for P. u altissi- 

 mum Brouss., * * * nomen." In any case the name P. altissimum is preoc- 

 cupied. 



