POLYGOKACEAE (BUCKWHEAT FAMILY) 



363 



broadly winged, 10-15 mm. long ; the wings often crisped, subentire ; achene 

 smoot h and shining, i mm. long. (P. dumetonim, var. Gray.) — Moist thickets, 

 comnion except on our northern borders. — Twining 2-4 m, over bushes. 

 (Japan.) 



31. P. dumetbrum L. Similar to the preceding ; fruiting calyx smaller, 

 5-7 mm. long; wings subentire; achene black, shining, 2.6-3 mm. long. — 

 Woods and rich open places, Mass. to Fla. and Tex., near the coast ; inland in 

 Miss, basin. (Eu.) Forma cristAtum (Engelm. & Gray) Robinson (P. crislatuvi 

 Engelm. & Gray) differs only in having the calyx-wings toothed. — Not rare 

 with and often scarcely distinguishable from the typical form. 



§ 7. PLEUR6ptERUS (Turcz.) B. & H. Erect perennials, unarmed; leaves 

 round-ovate ; flowers in panicled racemes. 



32. P. cnspinXTUM Sieb. & Zuoc. Stout and tall, glabrous except in the loose 

 axillary panicled racemes ; leaves round-ovate, shortly acuminate, truncate or 

 cordate at base ; outer sepals broadly winged in fruit. (P. Zuccarinii Small.) 

 — Occasionally escaped from gardens. (Introd. from Japan.) 



5. FAGOP'^RUM [Toum.] L. Buckwheat 



Calyx petal-like, equally 5-parted. Stamens 8. Styles 3 ; stigmas capitate. 

 Achene 3-sided. Embryo large, in the center of the albumen, which it divides 

 into 2 parts, with veiy broad and foliaceous plaited and twisted cotyledons. — 

 Annuals, with triangular-heart-shaped or halberd-shaped leaves, semicylindrical 

 sheaths, and corymbose racemes of white, greenish, or rose-colored flowers. 

 (Name from fagus, the beech, and wvpbs, wheat, from the resemblance of the 

 grain to the beech-nut ; so the English name Buckwheat, from the German Buche, 

 beech.) 



1. F. ESCDLtNTUM Moench. (Buckwheat.) Smoothish ; flower with 8 

 honey-bearing yeUow-glands interposed between the stamens ; achene acute and 

 entire, smooth and shining. (P. Fagopyrum Karst.) — Old fields, remaining as 

 a weed after cultivation, and escaping into copses. June-Sept. (Introd. from 

 Eu.) 



2. F. tatAricum (L.) Gaertn. (India-wheat.) Flowers very small, on 

 shorter pedicels ; achene very dull and roughish, the sides sulcate. — An occa- 

 sional escape from cultivation, especially in n. N. E. and adjacent Canada. 

 (Introd. from Asia.) 



6. POLYGONfLLA Michx. 



Calyx 5-parted, petaloid, loosely persistent about the achene, the 3 inner 

 divisions often enlarging in fruit, in which case the outer are usually spreading. 

 Stamens 8. Styles 3, and achene 3-angular. Embryo slender, 

 straight or nearly so, toward one side of the albumen. — Slen- 

 der glabrous annuals or perennials, with 

 alternate mostly linear leaves jointed at the 

 base, and rather rigid truncate or oblique 

 naked sheaths or bracts. Flowers on solitary 

 pedicels (nodding in fruit) jointed near the 

 base, borne in slender panicled racemes. 

 (Diminutive of Polygonum.) 



1. P. articulata (L.) Meisn. Annual, 

 erect, branching, glaucous, 1-3 dm. high ; 

 leaves linear-filiform, deciduous ; flowers rose-color or white, 

 nodding, in very slender racemes, sepals subequal, all erect 

 and connivent about the fruit ; achene exserted, smooth. — ,j]g_ p americana. 

 Dry sandy soil, Me. and n. N. H. to N. J. and south w. ; also ^^^^^^ ^ j 

 in the interior, chiefly in the region of the Great Lakes. — An ■Q^^ „(■ f,.uiiing ^a- 

 anomalous species with the calyx of a Polygonum. Fic 715. cems x l. 

 2. P. americ^na (Fisch. & Mey.) Small. Perennial, frutes- Fruiting calyx x 2. 



71.^, p. articulata. 

 Branoh x 1. 

 Bit of fruiting raceme 

 xl. 



