230 POLYGONACEAE 



dentate or laciniate on the margin. Rocky places: Ariz. — s Utah — Calif. L. 

 Son. Mr-My. 



7. RtJMEX L. Dock, Sorrel. 



Perennial, or rarely annual, caulescent herbs, with thick roots. Leaves 

 alternate, entire or wavy, with thin brittly ocreae. Flowers green, perfect, 

 polygamo-monoecious or dioecious, pedicelled in distant or contiguous whorls. 

 Sepals 6, the inner three usually developing entire, toothed, or spiny crests and 

 one or more sometimes bearing a tubercle or callosity. Stamens 6. Ovary 

 1-celled, sessile; styles 3; stigmas peltate, tufted. Achenes 3-angled, usually 

 invested by the accrescent calyx, margined or winged. 



Flowers dioecious; foliage acid. 



Leaves with auricled or hastate bases. 



Inner perianth-lobes not developed into wings in fruit; achenes granular. 



1. R. Acetosella. 

 Inner perianth-lobes developed into wings in fruit; achenes smooth. 



2. R. Acetosa. 

 Leaves narrowed at the base, neither auricled nor hastate. 3. R. paucifolius. 



Flowers perfect, or andro-polyganious ; foliage not acid. 

 Inner perianth-lobes-entire, undulate, or denticulate. 

 Inner perianth-lobes in fruit without tubercles. 



Inner perianth-lobes in fruit more than 2 cm. broad; plants perennial, with 



deep-seated woody rootstock. 4. R. venosus. 



Inner perianth-lobes in fruit less than 1.5 cm. in diameter. 



Plants perennial, with clusters of tuberous roots; inner perianth-lobes in 

 fruit 1-1.5 cm. broad. 

 Achene 7 mm. long or more; imier perianth-lobes in fruit broader than 



long; plant low. 5. R. salinus. 



Achenes about 5 mm. long; inner perianth-lobes in fruit longer than 

 broad. 6. R. hymcnoscpalus. 



Plants with taproots or thickened rootstocks; inner perianth-lobes in 

 fruit 5-10 mm. broad. 

 Plants low, less than 3 dm. high, perennial, with short tuber-like root- 

 stock; fruit maturing before the inner perianth-lobes become enlarged. 



7. R. praecox. 

 Plants tall, perennial, with a taproot, not with a tuber-like root- 

 stock; inner perianth-lobes well enlarged in fruit. 



Basal leaves 2-3 cm. wide, acute or rarely rounded at the base. 



8. R. hesperius. 

 Basal leaves 5-20 cm. wide, rounded, cordate, or truncate at the 



base. 

 Inner perianth-lobes in fruit with rotinded apex, not conspicu- 

 ously punctate. 

 Inner perianth-lobes in fruit 8-10 mm. wide. 



9. R. confinis. 

 Inner perianth-lobes in frtiit 5-6 mm. wide. 



10. R. occidentalis. 

 Inner perianth-lobes abruptly pointed, conspicuously punctate. 

 Fruiting inner perianth-lobes about as broad as long, sinuate 



on the margin. 11. R. dvnsiflorus. 



Fruiting inner perianth-lobes longer than broad, sharply 

 dentate. 12. R. subalpinus. 



Inner perianth-lobes or at least one of them bearing a tubercle in fruit; perennials 

 with a taproot. 

 Only one perianth-lobe tubercled. 



Leaves dark green, more or less crisp; fruiting inner perianth-lobes 8-9 



mm. broad, reniforra. 13. R. Palientia. 



Leaves pale green, not crisp; fruiting inner perianth-lobes 5-6 mm. broad, 

 deltoid-ovate. 14. R. altissimus. 



All three perianth-lobes bearing tubercles. 



Leaves dark green, crisp; fruiting perianth-lobes ovate to reniform, den- 

 ticulate. 15. R. crispus. 

 Leaves pale green, not crisp; fruiting perianth-lobes deltoid, entire. 



16. R. mexicanus. 

 Inner perianth-lobes in fruit spinulose-toothed on the margin. 



Tall plants; lower leaf-blades cordate at the base; one tubercle. 



17. R. obtusifolius. 

 Low plants; lower leaf-blades narrowed at the base; three tubercles. 



18. R. marilimus. 



1. R. Acetosella L. Perennial, with a creeping rootstock; stem erect, 

 glabrous, 1-6 dm. high; leaf-blades hastate, 2.5-15 cm. long, obtuse or acute, 

 with entire or 1- or 2-toothed auricles; upper stem-leaves linear; perianth green 

 or purplish; achenes ovoid, 3-angled, 1.5 mm. long, exceeding the persistent peri- 



