POLYGONACE^. (BUCKWHEAT FAMILY.) 391 



obtuse ; sheaths naked ; flowers in axillary dusters, or forming long interrupted 

 and leafless racemes ; fruiting calyx ovate, minutely puberulent, closely invest- 

 ing the dull black achenium, the outer lobes keeled. — Cultivated ground. In- 

 troduced. July - Sept. — Stems 1° - 3° long. 



16. P. oilinode, Michx. Minutely pubescent; stem twining; leaves 

 ovate, cordate or somewhat hastate at the base, acuminate, petioled; sheaths 

 with a row of reflexed hairs at the base ; flowers in loose simple axillary and 

 panicled racemes ; fruiting calyx smooth, nearly including the smooth and shin- 

 ing achenium, the outer lobes slightly keeled. — Dry rocks on the mountains of 

 North Carolina, and northward. July - Sept. — Stem 3° - 9° long. 



17. P. dumetorum, L. Smooth; stem twining; leaves ovate, acuminate, 

 long-petioled, cordate or somewhat sagittate at the base ; sheaths naked ; flowers 

 in long axillary more or less leafy racemes ; fruiting calyx somewhat spatulate, 

 emarginate, much longer than the smooth and shining achenium, the outer lobes 

 winged and decurrent on the pedicel. (P. scandens, L.) — Low margins of 

 fields and thickets, Florida, and northward. 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 ones 

 smaller, pectinate-fimbriate. Stamens 8, the filaments filiform. Styles 3, fili- 

 form : stigmas entire, obtuse. Achenium 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 



1. T. flmbriata, Gray. (Polygonum fimbriatum, .Efl.) — Dry pine bar- 

 rens, Georgia and Florida. Sept. and Oct. — Stem branching above, 2° high. 

 Leaves l'-2' long. Sheaths smooth, adnate to the leaves, not longer than the 

 fringe, the lower ones imbricated. Spikes 2' -3' long, panicled, erect, the upper 

 ones pistillate, the lower staminate. Bracts pointed with a long and slender 

 awn. Outer calyx-lobes oblong, entire in the staminate flowers, fimbriate, like 

 the inner ones, in the pistillate ones. 



5. COCCOLOBA, Jacq. 



Flowers perfect. Calyx herbaceous, 5-parted, the tube enlarged and more or 

 less fleshy in fruit. Stamens 8. Filaments subulate. Styles 3 : stigmas entire. 

 Achenium nearly globose, included in and partly united with the persistent calyx. 

 Embryo straight in the axis of mealy albumen. — Trees or shrubs, with alter- 

 nate leaves, truncate sheaths, and small greenish flowers in axillary and terminal 

 racemes. 



1. C. uvifera, Jacq. (Sea-Grape.) Smooth ; leaves short-petioled, cori- 

 aceous, orbicular-cordate or reniform ; racemes terminal, rigid, erect ; pedicels 



