HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 131 
74. Panicum trichanthum Nees. 
? Milium microspermum Lag. Gen. & Sp. Nov. 2. 1816. ‘‘Habitat in Nova His- 
pania. Seminacommunicavit perill. D. Sessé.”’ We have not seen the type specimen 
and the short description applies equally well to P. trichoides. Fournier@ gives this 
as equivalent to P. trichanthum Nees. 
Panicum trichanthum Nees, Agrost. Bras. 210. 1829. ‘‘ Habitat in Brasilia aequa- 
toriali (Siber.—Vidi in Herb. Reg. Berol.) In regno Mexicano (ab Humboldt, Haenke.) 
(Vide in Herb. Willd. et Haenk.)’”’ Nees’s first citation, however, following the diag- 
nosis and preceding his discussion of this and P. trichoides is as follows: ‘‘ Panicum 
tricho[iJdes, H7umb. et K. * * * (fide Herb. Willd.)’? While Nees’s description 
distinguishes carefully between this species and P. trichoides, there is some confusion 
as to the specimens mentioned, since some are referable to P. trichanthum and some 
to P. trichoides. The specimen in the Willdenow Herbarium marked “ P. trichanthum” 
in Nees’s writing, which appears to be the specimen referred to as that of ‘‘Humb. 
et K.,’’ is accepted as the type. 
Panicum guayaquilense Steud. Syn. Pl. Glum. 1: 85. 1854. ‘‘ Jameson Hrbr. nr. 
560, Guayaquil.”’ The type, in the Steudel Herbarium, is labeled ‘“Savannis Guaya- 
quilensibus.”’ 
Panicum microspermum Fourn.; Hemsley, Biol. Centr. Amer. Bot. 3: 492. 1885. 
‘Panicum trichoides [Swartz, misapplied by] Ch. et Schl. in Linnea, VI. p. 33” 
and ‘Panicum trichanthum Nees Agrostol. Bras. p, 210,’’ are cited as synonyms, no 
description being given. Schlechtendal and Chamissob give without description 
P.. trichoides Swartz as the name of Schiede & Deppe’s no. 894, the specimen of which, 
in the Berlin Herbarium, is referable to P. trichanthum. Panicum microspermum as 
used by Hemsley, then, must be considered as based on P. trichanthum Nees. Four- 
nier@ later describes the species under the name P. microspermum Fourn., citing as 
synonyms the names given by Hemsley and also ‘‘ Milium microspermum Lag.,’’ which, 
since Fournier takes up Lagasca’s specific name, would be the basis of Fournier’s 
name as published by himself. While the identity of M. microspermum is doubtful 
all the specimens cited by Fournier are referable to P. trichanthum. 
DESCRIPTION. 
Plants often in large bunches; culms ascending from a decumbent base, as much as 
1 to 2 meters long, rather stout, glabrous; sheaths shorter than the internodes, ciliate, 
and usually with a villous ring at the juncture with the blade, 
otherwise glabrous or rarely pubescent toward the summit; 
ligules membranaceous, less than 0.5 mm. long; blades oblong- 
lanceolate, usually 10 to 15 ecm. long, 10 to 15 or rarely 25 mm. 
wide, cordate, rather strongly nerved, glabrous or puberulent, 
often pilose above the ligule; panicles 10 to 30 cm. long, the 
; axis glabrous, the numerous branches and branchlets and the 
ee ee long pedicels capillary, flexuous; spikelets 1.2 to 1.4 mm. long, 
ler’s no. 1643. 0.6 mm. wide, obovate-fusiform, acute; first glume less than one- 
fifth the length of the spikelet; second glume shorter than the 
sterile lemma, both 3-nerved and under a lens minutely bullate-rugose, often ruptured 
and breaking off as the fruit matures, as in P. trichoides; fruit 1.2 mm. long, 0.6 mm. 
wide. 
a Mex. Pl. 2: 22. 1886. db Linnaea 6: 33. 1831. 
