158 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Branches of panicle short or only the lower as much as 2 to 3 cm. long; 



panicle pale or greenish, the hustles irregular in length, the longer 



sometimes 1 to 1.5 cm. lojig. 



Blades mostly less than 1 cm. wide, often folded; panicle usually 



loosely or interruptedly spikelike, the branches usually not over 



1 cm. long 25. C. macrostachya. 



Blades flat, as much as 1.5 cm. wide; panicle tapering from near the 

 base, the lower branches as much as 3 cm. long. 



26. C. scheelei. 



Subgenus PTYCHOPHYLLUM (A. Br.) Hitehc. 



Mostly robust perennials (one species annual) with large flat plicate blades. Bristles 

 single below only the terminal spikelet of the ultimate branchlets, or rarely below all 

 the spikelets. Panicles simple or the secondary branchlets very short, the spikelets 

 or branchlets more or less secund. Spikelets mostly narrower and less turgid than in 

 Chaetochloa proper. Fertile lemma acute or apiculate, rugose or only obscurely cross- 

 wrinkled. Confined to tropical regions of both hemispheres. 



1. Chaetochloa barbata (Lam.) Hitehc. & Chase. 



Panicum barbatum Lam. Tabl. Encycl. 1: 171. 1791. "Ex Insula Franciae [Mauri- 

 tius]." The type has not been examined. 



Panicum costatum Roxb. Fl. Ind. ed. Carey 1: 314. 1820. "Introduced into the 

 Botanic Garden from Mauritius, by Captain Tennant, in 1802." The type has not 

 been examined. 



Panicum viaticum Salzm. ; Doell in Mart. Fl. Bras. 2 2 : 155. 1877. "Habitat in 

 sepibus et ad vias prope Bahia (Salzmann n. 706)." A duplicate type is in the Na- 

 tional Herbarium. Doell states that he has seen an authentic specimen of Panicum 

 barbatum Lam., which he cites as a synonym under P. viaticum. 



Chamaeraphis viatica Kuntze, Rev. Gen. PL 2: 770. 1891. Based on Panicum via- 

 ticum Salzm. 



Chamaeraphis costata Kuntze, Rev. Gen. PL 2: 771. 1891. Based on Panicum 

 costatum Roxb. 



Chaetochloa barbata Hitehc. & Chase, Contr. U. S. Nat. Herb. 18: 348. 1917. Based 

 on Panicum barbatum Lam. 



Chaetochloa barbata is described by Grisebach ' and Hooker 2 under Panicum 

 flavescens Swartz. 



DESCRIPTION. 



Plants annual; culms decumbent, spreading, often rooting at the lower nodes, 

 branching, glabrous, scabrous or villous near the pubescent nodes, as much as 2 meters 

 long, but often much less; sheaths compressed, ciliate, glabrous or papillose-hispid; 

 ligule about 1 mm. long, densely ciliate; blades narrowly elliptic, flat and rather thin, 

 the upper narrowed to a somewhat truncate base, the lower gradually narrowed to a 

 petiole, as much as 30 cm. long and 2.5 cm. wide, distinctly plicate in large specimens, 

 obscurely so in dwarf ones; panicles long-exserted, green, as much as 20 cm. long, the 

 rachis scabrous and villous, the branches ascending or spreading, as much as 4 cm . 

 long; spikelets oblong-elliptic, glabrous, about 2.5 mm. long, tending to be in two 

 rows along the branches, at least along the upper part, often clustered on branchlets 

 on the lower part of the branches, the pedicels very short, the bristles flexuous, 5 to 10 

 mm. long, usually rather numerous; first glume circular, one-third the length of the 

 spikelet, 3-nerved; second glume about two-thirds as long as the spikelet. ovate, 

 acute, 7-nerved; sterile lemma as long as the fertile, acute, 7-nerved, the palea about 

 as long and wdde as the lemma; fertile lemma elliptic, acute, a little over 2 mm. long, 

 strongly transverse-rugose, the palea inclosed to the tip. 



1 Griseb. Fl. Brit, W. Ind. 547. 1864. 2 Hook. f. Fl. Brit. Ind. 7: 56. 1896. 



