32. POLVGONACEAE 93 



2. Leaves linear; stem glabrous; fruit with smooth angles; road- 

 sides and waste places, occasional; adv. from the western 

 states M. Ihuaris (Pursh) Heimerl 



32. Polygonaceae Lindl. — Buckwheat Family 



1. Plants not climbing by tendrils; calyx-tube not enlarged in fruit; leaves 

 with sheathing stipules. 

 2. Sepals 6, the three inner ones becoming enlarged (valves) in fruit (ex- 

 cept in the first species) ; stigmas tufted 1. Rumex 



2. Sepals 5, sometimes 4, nearly equal; stigmas capitate. 



3. Leaves not hastate-deltoid, or if so, the stems climbing by prickles or 

 reclining. 

 4. Branches not at all adnate to the stem; flowers clustered (or if soli- 

 tar)' not pink and the leaves not linear) 2. Polygonum 



4. Branches more or less adnate to the internodes of the stem; stipular 

 sheaths oblique or truncate, glabrous; flowers solitary in the axils 

 of the bracts in slender panicled racemes; calyx pink; stamens 8; 



slender annual with linear leaves 3. Polygonella 



3. Leaves hastate-deltoid; stem erect, smooth; flowers white; mature 



achenes much exserted from the calyx 4. Fagopyrum 



\. Plants climbing by tendrils; calyx-tube conspicuously enlarged in fruit, 

 enclosing the achene; stipules obsolete; flowers in slender axillary and 

 terminal racemes 5. Brunnichia 



1. Rumex L. — Dock 

 1 . Leaves hastate, sometimes linear or lanceolate ; plants with acid 

 juice, dioecious or polygamous; rhizomes horizontal. 

 2. Calyx essentially unchanged in fruit; achenes glandular, dull, 

 much longer than the sepals; fields, roadsides, waste ground, 

 common; nat. from Eur. May-July. Field Sorrel or Sour 

 Dock R. acetosella L. 



2. Inner sepals winged in fruit, thin, reticulate, cordate, 3-4 mm 



wide, enclosing the smooth, glossy achene; sandy soil; Mad- 

 ison Co., McDonald; St. Clair Co., Eggert 



R. hastatulus Baldw. 



1. Leaves not hastate or markedly acid; flowers perfect; roots stout. 



3. Inner .sepals (valves) entire or merely denticulate. 



4. Leaves flat, not crisped, pale green or glaucescent, acute at 



each end; native species. 

 5. Pedicels about equalling or shorter than the valves, curved. 



6. Only one valve (rarely two or three) bearing a tubercle; 

 valves 4-5 mm long; leaves lanceolate; roadsides and 



alluvial soil, common. June. Pale Dock 



R. altissimus Wood 



6. Usually all three (rarely only 2) valves bearing a tuber- 

 cle; valves 2.5-3 mm long; leaves linear-lanceolate; 

 sandy soil, not common; throughout the state. June. 



[R. mexicanus sensu auth., non Meisn.] 



R. triangulivalvis (Danser) Rech.f. 



