POLYGONACE^E. (BUCKWHEAT FAMILY.) 391 



obtuse ; sheaths naked ; flowers in axillary clusters, 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. cilinode, 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 

 spikes. 



1. T. fimbriata, Gray. (Polygonum fimbriatum, Ell.) 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- 



