HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 141 
81. Panicum megiston Schult. 
Panicum altissimum Meyer, Prim. FI, Esseq. 63. 1818, not DC. 1817.4 “In sylvis 
humidis plantationis Hof van Holland,’’ Essequebo or British Guiana. We have seena 
portion of the type in the Trinius Herbarium. The type is in the Géttingen 
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, “‘ ab. 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, Rév, Gram, 1:38.1829. Based on P. altissimum Meyer. 
Panicum equisetum Nees; Doell in Mart. Fl. Bras. 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,’’ 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 Meyer states that the culms ascend to a height of 20 
specimen of P.allissimum 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, isentire. This is simple and measures but 1.2 meters in height. 
This species somewhat resembles P. oaracense 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. 
Cusa: St. Cruz de los Pinos, Wright 3872. 
VENEZUELA: Santa Catalina, Rusby & Squires 355. 
Braz: Without locality, Riedel 1239, Gardner 1179. 
Paraauay: Morong 813, 1072. 
Ecuapor: Balao, Eggers 14345. 
a@ Roem. & Schult. Syst. Veg. 2: 457. 1817. The diagnosis is here referred to 
De Candolle ‘‘ Hornem. Hort. Hafn. 1, p. 84.’’ The latter work we have not seen, nor 
that cited by the Index Kewensis, ‘‘Elench. Hort. Monsp. 42. 1805,” for P. ‘‘altissi- 
mum Brouss., * * * nomen.’ In any case the name P. altissimum is preoc- 
cupied. 
