282 ORDER 104. POLYGONACE.E. 



6. THYSANELLA, Gray. Fls. $ * ? . Cal. colored, 5-parted, lobes 

 all erect, the 2 outer cordate, the 3 inner smaller, pectinate-fringed. Sta. 

 8. Styles 3. Achenia 3-angled, acuminate. A smooth, erect herb, with 

 the habit of Polygonella. (Polygonum, Ell.) 



T. fimbriata Gr. Pine-barrens, Ga., Fla. Stem branched, 2 3f. Sheaths bristle- 

 fringed. Lvs. linear, 12'. Fls. rose-white, in crowded, panicled spikes. July Oct. 



7. POLYGONELLA, MX. Calyx colored, 5-sepalled, persistent. Sta. 

 8, included. Styles 3 or almost 0. Ach. 3-cornered, naked or enclosed in 

 the 3 inner sepals enlarged and become scarious valves. Embryo straight. 

 Herbs or delicate shrubs, with very narrow leaves and the small flow- 

 ers solitary in each ochrea. 



Fls. dioecious. Pedicel 1". Filaments all filiform. Stig. nearly sessile.. .Nos. 1 3 

 Fls. all 5 . Pedicel 2". The 3 inner filaments dilated. Styles manifest. . .Nos. 4, 5 



1 P. parvifolf a MX. Shrubby, branches strict, leafless above ; Ivs. linear-cuneate ; 



panicle oblong ; inner sepals equalling the acute achenia. S. 1 2f. 



2 P. gracile N. Annual, glaucous ; branches filiform ; leaves spatulate; 3 inner sepals 



exceeding the pointed achenia. Dry sands, S. 2 3f. 



3 P. Croomia Chapm. Shrubby ; branches slender ; leaves linear (23") ; 3 valves 



unequal, 2 roundish, 1 oblong, exceeding the achenia. Uplands, S. 



4 P. aHeisnerlana Shutt. Shrubbj', very leafy, leaves linear, filiform, 6 10", ever- 



green, ochrea tipped with a white membrane ; 2 outer sepals reflexed. Uplands, Ga., 

 Ala., Fla. 1 2f. A delicate bushy shrub. 



5 P. artlculata Meisn. Annual, strict, with erect branches, which are soon nearly 



naked ; leaves linear, caducous from the tops of the truncate sheaths ; sepals fleeh- 

 colored, expanding. Dry. N. J., and W. : rare. 



8. POLYGONUM, L. KNOT-GRASS. Calyx of 5 sepals, rarely fewer, 

 colored or greenish, similar, imbricated in bud, at length all connivent, 

 persistent. Sta. 8, rarely fewer. Sty. 2 or 3, mostly 3, short filiform. Ach. 

 3-cornered or lens-shaped, enclosed in the dry, withered calyx. Embryo 

 curved, lateral, lying in a groove at one angle of the albumen. Herbs with 

 orlireate-jointed stems and small, white, red, or greenish fls. June Sept. 



Stems armed with retrorse prickles. Lvs. cordate-sagit. ECHINOCAULON. .Nos. 21, 22 



Stems unarmed, twining. Leaves cordate-hastate. TDJIARIA Nos. 1820 



Stems erect or decumbent, unarmed. Leaves hardly ever cordate. . .(*) 



* Calyx unequally 4-cleft. Styles 2, long deflexed. TOVARIA No. 17 



* Calyx equally 5-parted. Styles erect. . .(a) 



a Sheaths salver-form. Stamens 7. Style 2-parted. Tall. AMBLYOGONUM...NO. 16 

 a Sheaths subcylindrical. Stamens 5, 6, 8. Styles 2 or 3. . . (b) 



b Flowers in leafless, terminal, spike-like racemes. PERSICARIA.. .(c) 

 b Flowers axillary, or seldom forming a leafy raceme. . .(e) 



c Eaceme 1, dense. Stem at base or rhizome decumbent Nos. 14, 15 



c Racemes several. Sheaths naked, not fringed Nos. 12, 13 



c Racemes several. Sheaths bristly, fringe-ciliate . . . (d) 



d Style 2-(or 3-)cleft. Achenia flat or lens-shaped Nos. 9 11 



d Style 3-cleft. Acheuia sharply 3-cornered Nos. 58 



e Achenium protruding beyond the calyx, 3-angled Nos. 3, 4 



e Achenium included in the calyx, 3-angled Nos. 1, 2 



1 P. a vioulare L. Bird's K. Doorweed. Procumbent, diffuse ; leaves lance-ellip- 



