82 POACEAE 



the second scale 3-nerved, a little shorter than the 7-nerved third, the fourth scale slightly 

 exceeding the tliird, deep chestnut brown when mature, striate, apiculate. 

 In sandy soil, Illinois to tlie Indian Territory. Georgia and Texas. Summer. 



3. Syntherisma leucocomum 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, rougli 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; fir.st 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 tlian the fourtli, 7-nerved, the fourth scale 

 brown at maturity, striate, apiculate. 



In high pine lauds, Florida. Summer. 



4. Syntherisma gracillimum (Scribn. ) Nash. Stems tufted, 6-8 dm. tall, the inno- 

 vations mostly about 5 as long : lower leaf-sheaths somewhat hii:sute 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 iuHorescence 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 Avanting, 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 nun. wide or less, involute when dry, 

 smootli, densely pubescent above at the ))ase, 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 cm. 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, tlie first one wanting, the second about ^ as long as the spikelet, acute or acutish, 

 3-nerved, the third a little shorter than tlie fourth wliich is deep chestnut l^rown when ma- 

 ture, elliptic, obtusely apiculate and rather faintly striate. 



In dry sandy soil, Florida. Summer. 



6. Syntherisma Simpsonii (Yasey) 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 fii-st one usually wanting, 

 the second and third about equal in lengtli, 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 serotinum Walt. Stems 2-5 dm. long, finally branched, prostrate 

 at the base and rooting at the lower nodes : leaf-sheatlis, 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 J as long as the spikelet, 3-nerved, the fourth a little 

 longer than the third, white, ovate-lanceolate, acute. l^Panicum serotinum Trin.] 



In low open grounds, Delaware to Florida and Mississippi. Summer. 



8. Syntherisma humifusum ( Pers. ) Rydb. Stems 2-5 dm. long, finally branched, 

 IJrostrate and forming large mats: leaf -sheaths glabrous; blades 1.5-15 cm. long, 2.5-6 

 mm. wide, erect or nearly so, smootli and glabrous on both surfaces : axis of the inflores- 

 cence 1-3 cm. long ; racemes 2-5, 2-8 cm. long, Anally 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 tlie 7-nerved third, the fourth one a little longer than the third, deep 

 chestnut brown when mature, striate, acute. [Panicum glabrmn Gaud.] 



In waste places and fields, Ontario to Kansas, Florida and Louisiana.— A form, S. humifusum Mis- 

 sissippiemc ((iattinger) Nash, differs from the above in having usually longer racemes and the first scale 

 of the spikelet generally present. Cedar barrens, Nashville, Tenu. Summer. 



9. Syntherisma setosum ( Desv. ) Nash. Stems tufted, 4-10 dm. tall, finally branched, 

 decumbent at tlie base and rooting at the lower nodes : leaf-sheatlis, excepting the upper- 



