11 
§2, ARTHROLOPHIS. 
Racemes mostly in pairs, rarely digitate or panicled, the lateral ones 
sessile; joints of the rachis not translucent; flowering glume unusually 
bifid or 2-toothed, the rachis with a leaf-like bract at the first joint be- 
low ; pediceled spikelet empty, reduced to 1 or 2 glumes, 
(a) Sheathing bracts at the base of the spikes and equaling or longer than them. 
7, A, macrourus Mich. (Gray’s Manual, 6th ed., p. 638, Chapm. FI. 8. States, p. 
582.) Culms stout, 2 to 4 feet high, much branched, especially at the summit; 
panicle 4 to 20 inches long, dense, cymose clustered; racemes in pairs, slender, about 
1 inch long, 5 to 8 joints; rachis and sterile pedicels clothed with long white hairs; 
sessile spikelets about 2 lines long, linear; first glume linear, smooth except on the 
margins, 2-nerved, bidentate; second glume keeled, acute; third and fourth glume 
scarious; fourth awned ; sterile pedicel longer than the perfect flower; stamen 1. 
There are in the Southern States several varieties of this species, the principal of 
which are: 
Var. GLAUCOPSIS Ell\., with a more slender, fewer-flowered panicle, the leaves and 
culm smooth and glaucous. 
Var. VIRIDIS Chapm., also a more slender, open-panicled form, with leaves nar- 
rowly linear, the radical ones equaling or nearly equaling the culm, light green. 
Var. CORYMBOsuUS Chapm., in which the spikes are heavily clustered in a corym- 
bose form near the top of the culm. 
Var, PUMILUS, n. var. Perennial dwarf, tufted; culms 6 to 10 inches high, 
branching at the base and terminating in a cymose panicle; leaves 3 to 6 inchés 
long, longer than the internodes, smooth, the sheaths inlosing the lateral flowering 
branches, sparingly hairy at the throat, branches numerous at the upper sheaths, 
each subdivided, the sheathing bract rather longer than the terminal spikes, which 
are 1 to 1} inches long, and with 10 to 12 spikelets; pedicel slightly hairy below the 
bract. A remarkable variety, collected in western Texas (G. C. Nealley). 
8, A. Virginicus Linn. (Gray’s Manual, 6th ed., p.638.) (A. dissitiflorus Mich.) 
sulms appressed below, 2 to 4 feet high, slender, much branched, the branches short 
anderect ; leaves long and narrow and with the sheaths mostly smooth; sheathing 
leaves longer than the lateral branches, which are 2 to 3 inches long and twice or thrica 
subdivided, each pair of racemes sheathed with a bract longer than themselves; ped. 
icels short, slender; racemes about 1 inch long; rachis flexuous, 8 to 12 jointed, the 
sterile pedicel and upper part of the joints long hairy; sessile spikelet 14 lines long, 
lanceolate, acute, smooth except on the margins; awn 6to 8 lines long; stamen 1,— 
Massachusetts to Florida and coastwise to Texas. Var. GLAuCUS Hack., glabrous 
throughout.—Florida, Var. DEALBATUS Molir., sheaths and leaves becoming whit- 
ish.—Mobile. Var. TETRASTACHYUs Hack., spikes often in fours, lower sheaths, and 
leaves pubescent or villous.—Alabama to Florida, Var. STENOPHYLLUs Hack., culms 
shorter, leaves very short.—South Carolina. 
9. A. longiberbis Hack. in Flora, 1835, p. 131. Culms 2 to 3 feet high, sheaths 
more or less hairy ; leaves linear, 4 to 8 inches long, narrow; spikes in pairs, 1 to 14 
inches long, mostly rather shorter than the bract at the base, rather densely flow- 
ered; the rachis and pedicels covered with long white hairs; spikelets 2 lines long, 
awn 6 to 8 lines long.—Florida (Dr. Garber, 1837), 
10. A. Mohrii Hack., in litt. (A. Liebmanni, var. Mohrit Hack.) Culms 3 to4 
feet.high, robust, leafy; leaves and sheaths villous-pubescent, the lower distichous, 
blade narrow, 6 to 10 inches long; panicle 1 to 1} feet long; peduncles mostly in pairs 
or threes; bract about as long as the spikes or shorter; spikes in clusters of 3 to 7, 1 
to 2 inches long; rachis and internodes villose, brownish ; awn of perfect flower } to 
Linch long.—Florida (No. 3636, 4. H. Curtiss’ distribution), Mobile, Ala. (Dr Charles 
Moir), and Ocean Springs, Mississippi (S. M. Tracy). 
