$2 POACEAE 
the second scale 3-nerved, a little shorter than the 7-nerved third, the fourth scale slightly 
exceeding the third, deep chestnut brown when mature, striate, apiculate. 
In sandy soil, Illinois to the Indian Territory, Georgia and Texas. Summer. 
3. Syntherisma leucocómum Nash. Stems 1 m. tall or less: leaf-sheaths coarsely 
striate, the lower one densely hirsute with nearly appressed hairs; blades erect, often invo- 
lute when dry, smooth beneath, rough above, those on the stem 1.5-2.5 dm. long, those 
on the innovations 1-4 dm. long: axis of the inflorescence 4-6 cm. long; racemes 2-4, 
2-2.5 dm. long, erect or nearly so, alternate : spikelets 2.25-2.5 mm. long, 0.8 mm. wide, 
elliptic, acute, usually in 3's; first scale wanting, the second and third scales appressed- 
pubescent with very long glandular-tipped hairs, the second scale about as long as the 
fourth, 3-nerved, the third scale a little longer than the fourth, 7-nerved, the fourth scale 
brown at maturity, striate, apiculate. 
In high pine lands, Florida. Summer. 
4. Syntherisma gracíllimum (Scribn.) Nash. Stems tufted, 6-8 dm. tall, the inno- 
vations mostly about j as long: lower leaf-sheaths somewhat hirsute with ascending-ap; 
pressed hairs ; blades 2 mm. wide or less, smooth beneath, rough above, those on the inno- 
vations 3-4 dm. long; axis of the inflorescence 3-6 cm. long ; racemes 2, or rarely 3, about 
3 dm. long, erect : spikelets slightly exceeding 2 mm. long, about 0.8 mm. broad, elliptic, 
acute, usually in 3’s, irregularly scattered ; scales glabrous, the first wanting, the second 
3-nerved, usually about } as long as the spikelet, the third scale 5-nerved, slightly shorter 
than the spikelet, the fourth scale deep seal brown when mature, conspicuously striate, ob- 
tusely angled on the back, apiculate. 
In high pine lands, Florida. Summer. 
5. Syntherisma Bakeri Nash. Stems tufted, 1 m. tall or less: lower leaf-sheaths 
densely hirsute with ascending hairs; blades 2 mm. wide or less, involute when dry, 
smooth, densely pubescent above at the base, those on the innovations 2-4 dm. long, those 
on the stem 1-2.5 dm. long: axis of the inflorescence 4-7 cm. long ; racemes usually 3, 
14-22 em. long, densely long-pilose at the base: spikelets about 2.25 mm. long, 0.8 mm. 
wide, elliptic, usually in 3’s; scales glabrous, excepting the sparsely pilose apex of the 
second, the first one wanting, the second about $ as long as the spikelet, acute or acutish, 
3-nerved, the third a little shorter than the fourth which is deep chestnut brown when ma- 
ture, elliptic, obtusely apiculate and rather faintly striate. 
In dry sandy soil, Florida. S- mmer. 
6. Syntherisma Simpsónii (Vasey) Nash. Stems 8-12 dm. long, finally branched, 
prostrate at the base and rooting at the lower nodes : leaf-sheaths copiously papillose-hir- 
sute with spreading hairs; blades 7-30 cm. long, 5 mm. wide or less, papillose-hirsute on 
both surfaces : axis of the inflorescence 4-6 cm. long ; racemes 6-8, 10-13 cm. long, erect 
or ascending, usually scattered : spikelets a little exceeding 3 mm. long, about 1 mm. 
wide, elliptic-lanceolate, acute, in pairs; scales glabrous, the first one usually wanting, 
the second and third about equal in length, the former 5-, the latter 7-nerved, the fourth 
a little shorter than the third, elliptic, acute, yellowish white, finely striate. 
In moist saline soil, Florida. Summer. 
7. Syntherisma serótinum Walt. Stems 2-5 dm. long, finally branched, prostrate 
at the base and rooting at the lower nodes: leaf-sheaths, especially the lower ones, papil- 
lose-hirsute with spreading hairs ; blades 1.5-10 cm. long, 3-10 mm. wide, ascending, pu- 
bescent on both surfaces: axis of the panicle 1-2 cm. long; racemes 2-6, 2.5-10 cm. long, 
ascending, usually alternate : spikelets about 1.5 mm. long, about 0.6 mm. wide, elliptic, 
acute, usually in pairs; first scale wanting, the second and third appressed-pubescent with 
long hairs, the second one about 4 as long as the spikelet, 3-nerved, the fourth a little 
longer than the third, white, ovate-lanceolate, acute. [Panicum serotinum Trin. ] 
In low open grounds, Delaware to Florida and Mississippi. Summer. 
8. Syntherisma humifüsum (Pers.) Rydb. Stems 2-5 dm. long, finally branched, 
prostrate and forming large mats: leaf-sheaths glabrous; blades 1.5-15 cm. long, 2.5- 
mm. wide, erect or nearly so, smooth and glabrous on both surfaces: axis of the inflores- 
cence 1-3 cm. long ; racemes 2-5, 2-8 cm. long, finally widely spreading, alternate : spike- 
lets slightly exceeding 2 mm. long, about 1 mm. wide, elliptic, acutish, usually in pairs; 
first scale usually wanting, the second and third appressed-pubescent, the 3-nerved second 
about equalling the 7-nerved third, the fourth one a little longer than the third, deep 
chestnut brown when mature, striate, acute. [Panicum glabrum Gaud.] 
In waste places and fields, Ontario to Kansas, Florida and Louisiana.—A form, S. humifusum Mis- 
sissippiénse papery Nash, differs from the above in having usually longer racemes and the first scale 
of the spikelet generally present. Cedar barrens, Nashville, Tenn. Summer. 
9. Syntherisma setdsum ( Desv.) Nash. Stems tufted, 4-10 dm. tall, finally branched, 
decumbent at the base and rooting at the lower nodes: leaf-sheaths, excepting the upper- 
