412 POLYGONACEJE. (BUCKWHEAT FAMILY.) 



greenish, curved; styles at length hooked at the apex. Dry rich soil. Au- 

 gust-Sept. 11 Plant 2 -4 high. Leaves 3' -5' long, H'-2|' wide. 

 Spike 6' -12' long. 



5. ECIIIXOCAULON. Flowers in terminal clusters: calyx 4- ^-parted: sta- 

 mens 6 or 8 : stt/les 2 -3 : achemum lenticular or 3-angled : cotyledons accum- 

 bent. Stems weak, branching, armed on the angles, petioles, etc. with recurrl 

 prickles. 



15. P. arifolium, L. Leaves hastate, acuminate, membrauaceous, mi- 

 nutely dotted and hairy, long-petioled, the lobes acute; peduncles rather short, 

 bristly ; (lowers white, somewhat spiked ; stamens 6 ; styles 2 ; aehenium 

 lenticular. Rice fields and wet places, South Carolina, and northward. 

 June -Oct. Stems 2 -3 long. Leaves 3' -4' long. 



16. P. sagittatum, L. Leaves small, sagittate, acute, short-petioled, 

 smooth ; peduncles elongated, smooth ; flowers white, capitate ; stamens 8 ; 

 styles 3 ; aehenium 3-angled. Wet places. June - Oct. (T) Stem 1- 3 

 long. Leaves 1'- 2' long. 



6. TINIARIA. Flowers in axillary clusters or racemes: calijx greenish 

 white, 5-j>arted, the outer lobes keeled or winged on the back : stamens 8 : styles 

 3, very short: aehenium 3-angled: cotyledons decumbent. Annuals, with 

 twining stems and cordate leaves. 



17. P. Convolvulus, L. Stem roughish, when small erect; leaves 

 long-petioled, sagittate-cordate, acuminate ; sheaths naked ; flowers in axillary 

 clusters, or in long interrupted leafless racemes ; fruiting calyx ovate, closely 

 investing the dull black achemum, the outer lobes keeled. Cultivated ground. 

 Introduced. July - Sept. Stems 1 - 3 long. 



18. P. cilinode, Michx. Minutely pubescent; leaves ovate, acuminate; 

 sheaths bearded at the base ; flowers in loose simple axillary and panicled 

 racemes ; fruiting calyx nearly including the smooth and shining aehenium, 

 the outer lobes slightly keeled. Dry rocks on the mountains of North Caro- 

 lina, and northward. July - Sept. Stem 3- 9 long. 



19. P. dumetorum, L. Smooth; leaves ovate, acuminate, long-peti- 

 oled ; sheaths naked ; flowers in long axillary more or less leafy racemes , 

 fruiting calyx somewhat spatulate, emarginate, much longer than the smooth 

 and shining acheninm, the outer lobes winged, and decurrent on the pedicel. 

 Low margins of fields and thickets. June - Sept. Stem 6 - 12 long. 



4. THYSANELLA, Gray. 



Flowers polygamous. Calyx corolla-like, deeply 5-parted, unchanged in 

 fruit ; lobes erect, unequal ; the 2 outer ones cordate at the base ; the inner 

 smaller, pectinate fimbriate. Stamens 8. Styles 3. Aehenium ovate, 3 

 angled, nearly included in the persistent calyx. Cotyledons on the outside of 

 the albumen. An erect smooth and branching annual, with long linear 

 acute leaves, truncate cylindrical sheaths, fringed with long bristles, and 

 white or rose colored flowers in closely bracted spikes. 



1. T. fimbriata, Gray. (Polygonum fimbnatum, Ell.) Dry pine bar- 

 rens, Georgia and Florida. Sept. - Oct. Stem branching above, l-2 a 

 high. Leaves 1'- 2' long. 





