POLYGONE.i:. 141 



lowest broader, not at all hastate, 2-4 in. loug. acutish, narrowed to a 

 slender petiole : jjanicle naked, its branches slender, erect : fl. in loose 

 fascicles Ja ^^^^ long, fruiting sparingly : pedicels filiform, jointed near 

 the base : valves cordate-ovate, entire, nearly 2 lines long. — Near Lake 

 Tenayo in the Sierra Nevada, Brewer, thence northward and eastward. 



12. R. digrynus, Linn. Sp. PI. i. 337 (1753) ; Hill, Veget. Syst. x. 24 

 (1765), under Oxyria; Mill. Diet. 8th ed. (1768), under Acetosa; Wahlb. 

 Fl. Lapp. 101. t. 9 (1812), under Rheum. Stoutish and somewhat fleshy, 

 6—18 in. high, the stems usually several, from a perpendicular simple or 

 branched fleshy root : leaves mostly radical, long-petioled, round- 

 reniform, 1 — 2 in. broad : fl. perfect, greenish or reddish, in scarious 

 bracted fascicles forming panicled racemes, dimerous, the sepals 4, 

 stamens 6 and stigmas 2 : achene thin, flat, broadly winged, the wing 

 exserted from the two spatulate erect inner sepals, red in age. — Common 

 in cold wet rocky places, along snow-fed streamlets etc., in the higher 

 Sierra ; and in like situations far northward around the whole circuit of 

 the northern hemisphere ; a merely dimerous and wing-fruited sorrel, 

 formerly cultivated in northern Europe — like other Acelnsa species — for 

 its tender and keenly acid fruit-like and wholesome herbage. 



13. E. AcETOSELiiA, Linn. 1. c. 338. Acelosa tenuifolia, Mcench, Meth. 

 357 (1794) ; A repens, S. F. Gray, Nat. Arr. ii. 276 (1821). Stems erect 

 from running rootstocks, slender, 6 — 18 in. high : leaves oblong- to 

 linear-lanceolate, or oblanceolate, 1 — 3 in. long, usually hastate, the lobes 

 often toothed : panicle naked, long and narrow ; fl. dioecious, small, red, 

 in loose fascicles ; pedicels short, jointed at top : achene small, ovate- 

 triqiietrous, '^-^ line long. Very common, and one of the most persistent 

 of field and pasture weeds, multiplying excessively both by seeds and by 

 its rootstocks ; native of the Old World, but now nati^ralized in all 

 temperate regions of the globe. 



3. EMEX, Necker. Annual herbs with alternate leaves, and axillary 

 solitary or clustered unisexual flowers. Staminate perianth 5— 6-parted; 

 segments equal, spreading. Stamens 4 6 ; filaments filiform. Fertile 

 perianth with urceolate tube and 6 unequal lobes in 2 series, the whole 

 accrescent in fruit and indurated ; the outer lobes spreading and spines- 

 cent, the inner plane, erect-connivent. Fruit a triquetrous achene 

 enclosed in the tube of the perianth but free from it. Seed subterete ; 

 embryo incurved. 



1. E. AUSTRALis, Steinh. Ann. Sc. Nat. ix. 195 (1838) : E. Centropodium 

 Meisn. Linnsea, xiv. 490 (1840). Glabrous ; the stout and rigid prostrate 

 branches 1-2 ft. long : leaves triangular-ovate, entire, 2 in. long, at base 

 abruptly narrowed to a long petiole : staminate fl. often clustered at the 

 end of a peduncle ; the pistillate sessile : fructiferous perianth I3 — % 



