POLYGONACEAE 



367 



FAMILY 1. POLYGONACEAE Lindl. BUCKWHEAT FAMILY. 

 Characters of the order. 



Flowers or flower-clusters in involucres of partially united bracts : stamens 9. 1. ERIOGONUM. 



Flowers or flower-clusters not involucrate : stamens 4-8. 



Hypanthium little or barely developed, at least not investing the achene. 



Stigmas tufted. 2. RUMEX. 



Stigmas not tufted. 



Internodes of the stem and branches partially adnate. 



Inner sepals not fimbriate, often conspicuously accrescent. 



Flowers polygamo-dioecious : filaments subulate : embryo axile. 3. POLYGONELLA. 



Flowers perfect : filaments various, the 3 inner dilated : embryo lateral. 4. GONOPYRUM. 

 Inner sepals fimbriate, or in fruit-producing flowers all fimbriate, not 



accrescent. 5. THYSANELLA. 



Internodes of the stem and branches not adnate. 



Leaf-blades jointed at the base : ocreae 2-lobed, becoming lacerate : fila- 

 ments, at least the inner, dilated. 6. POLYGONUM. 

 Leaf-blades not jointed at the base : ocreae various, not 2-lobed : fila- 

 ments slender. 

 Ocreae cylindric, truncate. 



Sepals 4 : calyx curved : stamens 4. 7. TOVARA. 



Sepals 5, if fewer, the stamens more than 5 : calyx not curved. 8. PERSICARIA. 



Ocreae oblique, more or less open on the side facing the leaf. 



Herbs, various in habit, not vines : sepals neither keeled nor winged. 

 Racemes collected into terminal corymbs : embryo dividing the 



endosperm by an S-shaped curve : plants smooth. 9. FAGOPYRUM. 



Racemes not in terminal corymbs : embryo slender, at one side 



of the endosperm : plants prickle-armed. 10. TRACAULON. 



Vines with twining stems : outer sepals winged or keeled. 11. TINIARIA. 



Hypanthium well developed, enclosing the achene. 



Hypanthium winged at maturity : stigmas 2-cleft. 12. BRUNNICHIA. 



Hypanthium not winged : stigmas not cleft. 13. COCCOLOBIS. 



1. ERIOGONUM Michz. 



Annual or perennial herbs or shrubby plants. Leaves basal or cauline, alternate, 

 opposite or whorled : blades entire : ocreae wanting. Flowers perfect, or polygamo- 

 monoecious, the involucrate clusters variously disposed. Involucres varying from turbinate 

 to almost cylindric, 5-8-lobed. Calyx more or less colored, jointed to a short pedicel 

 which is subtended by a minute bractlet. Sepals 6, equal, or the outer ones larger. Stamens 

 9 : filaments filiform, often villous. Ovary 1-celled, very narrowly pyramidal : styles 3 : 

 stigmas capitate. Achene 3-angled, more or less swollen at the base, invested by the 

 accrescent calyx. Embryo axile or eccentric in the mealy endosperm. 



Calyx narrowed into a stipe-like base. 



Leaves whorled ; blades relatively broad : inflorescence with leaf-like bracts. 

 Leaves alternate ; blades relatively narrow : inflorescence naked. 



Peduncles mostly over 1 cm. long : calyx 6-10 mm. long : involucres over 5 



mm. high. 

 Peduncles mostly less than 1 cm. long : calyx 4-5 mm. long : involucres less 



than 5 mm. high. 

 Calyx without a stipe-like base. 



Annual : leaf-blades much longer than broad. 



Outer sepals obovate, not cordate : achenes 1.5 mm. long. 

 Outer sepals suborbicular, cordate : achenes 3 mm. long. 

 Perennial by a shrubby caudex : leaf-blades as broad as long or nearly so. 



1. Eriogonum tomentosum Michx. Perennial by a gnarled rootstock, tomentose 

 with brown or reddish hairs. Stems often clustered, 4-12 dm. tall, corymbosely branched 

 above : basal leaves 5-15 cm. long ; blades oblong, oblanceolate or spatulate, long-petioled : 

 stem-leaves in whorls of 3-5 ; blades ovate or obovate or sometimes oblanceolate, sessile or 

 short -petioled, tomentose beneath : bracts usually elliptic or oval : involucres campanulate, 

 about 4 mm. high, sessile in a whorl of bractlets : calyx white, turbinate, 4-5 mm. long, 

 becoming 10 mm. long, at maturity : sepals tomentose without, the inner larger and thinner 

 than the outer : filaments villous at the base : achenes 3-angled, ovoid, 5 mm. long, villous 

 at the top. 



In dry pine lands or on sand hills, South Carolina to Florida and Alabama. Spring to fall. DOG- 

 TONGUE. 



2. Eriogonum Floridanum Small. Perennial by a stout rootstock. Stems 6-10 

 dm. tall, branched above, densely scaly at the base : leaves rather numerous at the base of 

 the stem, 1-2 dm. long ; blades broadly or narrowly linear, narrowed to the base, but with 

 little distinction into blade and petiole : peduncles mostly over 1 cm. long : involucres 

 6-7 mm. high : calyx 6-10 mm. long, green : sepals linear-subulate, attenuate, involute, 

 copiously pubescent without : achenes 3-angled. 



In sand or sandy soil, Florida. Summer and fall. 



1. E. tomentosum. 



2. E. Floridanum. 



3. E. longifolium. 



4. E. annuum. 



5. E. multiflorum. 



6. E. tenellum. 



