32. POLYGONACEAE 97 



6. Style long, exserted, persistent, reflexed in fruit; calyx curved, 

 4-parted; racemes slender, rigid, greenish; leaves ovate, 

 acuminate; woods, common. July-Sept. [Tovara virgini- 



ana (L.) Raf.] Jump-seed. Virginia Knotweed 



- P. virginianum L. 



5. Outer sepals keeled or winged at maturity. 

 19. Stems twining or trailing. 



20. Outer sepals becoming conspicuously winged; achenes 



smooth, glossy; plants perennial. 



21. Mature fruiting calyx 8-10 mm long, the wings 



imdulate or crisped; achenes 3.5-4.5 mm long; 



along fences, or borders of woods and thickets, 



common. July-Oct. Climbing False Buckwheat 



P. scandens L. 



21. Mature fruiting calyx 5-9 mm long, the wings flat; 

 achenes 2-3 mm long; open woods, occasional. 



Aug. -Sept. [P. dumctorum of auth., not L.] 



- P. cristatum Engelm. & Gray 



20. Outer sepals merely keeled at maturity; plants annual; 

 achenes minutely roughened, dull, black, 3-4 mm 

 long; fields and waste places, common throughout 111.; 



nat. from Eur. June-Sept. Black Bindweed 



P. convolvulus L. 



19. Stems tall, stout, erect. 



22. Leaves 5-15 cm long, tn_mcate or rounded at base; stems 

 1-2.5 cm tall; inflorescence lax, some of the axillaiy 

 racemes much longer than the petioles; occasionally in 

 waste ground about towns, spread from cult, and often 

 fonning vigorous colonies; native of Japan. July-Oct. 

 [P. sicboldii de Vriese; P. ziiccarinii Small]. Japanese 



Knotweed. Mexican-bamboo 



P. cuspidatum Sieb. & Zucc. 



22. Leaves 30-40 cm long, shallowly cordate at base; stems 

 2.5-4 m tall; inflorescence dense, the axillary racemes 

 shorter than or equalling the petioles ; native of Sakha- 

 lin L: sometimes cultivated and occasionally estab- 

 lished in 111. Sacaline P. sachalinense F.Schmidt 



3. Polygonella Michx. — Join tweed 

 P. articulata (L.) Meisn. Sandy soil, locally in n. 111., extending 

 southward to Peoria and Kankakee counties. July-Oct. 



4. Fagopyrum Mill. — Buckwheat 

 F. esculentum Moench. Fields or roadsides, occasionally escaped 

 from cult.; introd. from Eur. July-Sept. 



5. Brunnichia Banks 

 B. cirrJiosa Banks. River banks, thickets, or along fences, not com- 



