POLYGONACEAE (BUCKWHEAT FAMILY) 153 



appressed, and unchanged in fruit. Stamens 6. Stigmas 2, tufted. Achene 

 orbicular-winged. 



1. Oxyria digyna (L.) Camptdera, Rumex, pi. 3, fig. 3. 1819. Rather 

 stout and fleshy, 8-40 cm. high, glabrous: flowers in scarious-bracted fascicles, 

 on short capillary pedicels: sepals often reddish, the outer carinate and darker 

 than the inner. At high altitudes in cold wet places among rocks throughout 

 the northern hemisphere. 



3. RUMEX L. DOCK. SORREL 



Coarse perennial herbs: stems le.afy, with obliquely truncate cylindrical 

 naked sheaths. Flowers small, fascicled or verticillate in paniculate racemes, 

 perfect, polygamous, or dioecious, without involucre. Sepals 6; the outer 

 spreading; the inner somewhat colored and developing reticulate wings. 

 Stamens 6. Stigmas 3, peltate, tufted. The foliage in some species is dis- 

 tinctly acid. 



Flowers dioecious; inflorescence slender and leafless. 



Inner sepals becoming winged; achene granular . . . 1. R. Acet9sella. 

 Inner sepals not winged; achene smooth . . . . 2. R. paucifolius. 



Flowers perfect or polygamo-monoecious; inflorescence with 



stouter often leafy branches. 

 Inner perianth-segments (valves) very large (10-30 mm. 



broad), usually rose-colored. 

 Perennial from rootstocks . . . . . . 3. R. venosus. 



Perennial from large clustered tuber-like roots. 



Fruiting valves cordate-reniform . . . . 4. R. salinus. 



Fruiting valves ovate-cordate . . . . . . 5. R. hymenosepalus. 



Inner perianth-segments (valves) medium size (less than 10 



mm.), green or rose-color. 

 One or more of the valves bearing a callosity or tubercle on the 



back. 

 Wings entire, not toothed or fringed. 



Leaves flat, entire or merely undulate-margined. 



Stems tufted 6. R. mexicanus. 



Stems single . . . . . . . 7. R. brittanica. 



Leaves decidedly crisped on the margin. 



Tubercles 3 8. R. crispus. 



Tubercle 1 9. R. Patientia. 



Wings toothed or fringed. 



Lower leaves cordate at base 10. R. obtusifolius. 



Lower leaves narrowed at base 11. R. persicarioides. 



Valves without tubercles. 



Perennial from horizontal rootstocks . . . . 12. R. densiflorus. 

 Perennial from vertical roots. 



Hoots several, fascicled, fleshy 13. R. polyrrhizus. 



Root single 14. R occidentalis. 



1. Rumex Acetosella L.Sp. PL 338. 1753. Dioecious, 1-3 dm. high: leaves 

 small, rarely 5 cm. long; the lower mostly hastate, with a large decurrent 

 auricle on each side; the upper gradually reduced and entire: panicle more or 

 less compound, usually reddish, the filiform ascending branches leafless: 

 pedicels capillary, once or twice as long as the flower, articulated at summit; 

 flowers about 1.5 mm. long, the outer sepals granular. Naturalized from 

 Europe; not infrequent as a weed. Known as FIELD or SHEEP SORREL. 



2. Rumex paucifolius Xutt. Wats. King's Rep. 314. 1871. Somewhat 

 tufted, 2-4 dm. high: leaves linear to lanceolate or oblanceolate, attenuate to 

 a slender petiole: inflorescence with suberect branches: flowers reddish, in 

 loose fascicles; pedicels filiform, jointed near the base: valves about 4 mm. in 

 diameter, sometimes with a minute basal tubercle: achene small. [R. Geyeri 

 (Meis.) Trel. Rep. Mo. Bot. Card. 3: 78. 1892.] Mountain parks; Colorado 

 and Utah and far northward. 



3. Rumex venosus Pursh, Fl. Am. Sept. 733. 1814. Stem erect, 3 dm. 

 high or less, from running rootstocks, stout and leafy, with conspicuous di- 

 lated stipules : leaves on short but rather slender petioles, ovate or oblong to 

 lanceolate, 8-15 cm. long, only the lowest acute or somewhat cordate at base: 

 panicle nearly sessile, short, dense in fruit: valves entire, cordate-orbicular 



