28 Bulletin VII. 1. 



pubescent on the flattened back, five to seven-nerved; second 

 glume similar and equalling the first, convex below, subcarinate 

 above, acute, the hyaline inflexed margins ciliate; third glume a 

 little shorter than the outer ones, membranous, faintly two-nerved, 

 the infolded margins ciliate; fourth glume broadly oval, obtuse, 

 nearly one-half shorter than second, two-lobed or bidentate at the 

 apex, ciliate, awned. Awn five to eight lines long. Palea a little 

 shorter than its glume, nerveless, ciliate. 



Johnson-grass is now pretty well known in Tennessee, having 

 been introduced quite generally over the State. There are a few 

 who still regard it as a valuable grass for hay, and certainly its 

 yield is very large and the hay produced is excellent; but there are 

 a great many more who are ready to offer a handsome reward to 

 anyone who will free their lands from it. It has strong, under- 

 ground stems, which grow deeply, taking the soil completely. 

 This habit makes Johnson-grass exceedingly difficult to eradicate, 

 for the least fragment of these underground stems, if left in the 

 soil, serves to produce a new plant. Unless one wishes to give the 

 land up for an indefinite period to this grass, its cultivation ought 

 not to be undertaken. 



Tribe V. PANICE^.* 



Spikelets hermaphrodite, compressed from the back or not at 

 all flattened; glumes three or four, when four there is occasionally 

 a staminate flower or a palea in the axil of the third; the upper- 

 most or flowering g^lume of the hermaphrodite flower is always 

 firmer in texture than the outer glumes, of which the first is usu- 

 ally smaller than the others. Axis of the inflorescence not articu- 

 lated, the rachilla being articulated below the empty glumes, the 

 spikelets falling off singly from their pedicels. 



This is one of the largest tribes in the order Gramineae. It con- 

 tains twenty-two genera, with over 630 species. Fanicum, the princi- 

 pal genus, is the largest among grasses, numbering three hundred 

 species. The Fa?ucece are very widely distributed throughout the 

 tropical and temperate regions of the world. Crab-grass and the 

 millets [Setarix species) are among our best known examples of 

 this tribe. 



8. PASPALUM Linn. Syst. ed. 10, ii. 855 (1759). 



Spikelets one-flowered, plano-convex, nearly sessile in two to 

 four rows along one side of a continuous narrow or dilated rachis, 

 forming simple racemes, these either solitary or two or more to- 

 gether and digitate or paniculate; rachilla articulated below the 

 empty glumes. Glumes three (rarely only two or four) awnless, 

 usually obtuse, the first two empty, membranaceous, equal or 



*Trlbes III,, Zoysleae, and IV., Trlsteglneae, are not represented In Tennessee. They 

 are smaU tribes, together having only about sixty species, chiefly tropical. 



