REVISION OF RUMEX. 79 



reflexed even in flowering; valves orbicular, 5 mm. in 

 diameter, clawless, usually with a delicate callosity at base; 

 acbene 1.2x2.5 mm. Sp. i. (1753), 337; Meisner, DC. 

 Prod, xiv, 64. Apparently indigenous from Labrador to 

 Lake Superior, Alaska, and Oregon; and introduced from 

 the Old World at a few points in the Northern States 

 probably as a waif from gardens, in which it is sometimes 

 cultivated for its acid foliage. Specimens examined from 

 Labrador (Bryant, 1860), Toronto (Macoun, 1878) and 

 Point aux Pins, Canada (Macoun, 1869, 84), N. Shore 

 L. Superior (Pitcher), Quatcho Lake (Dawson, 1876), 

 Morley (Macoun, 1885), and Arctic N. A. (Richardson on 

 Franklin Exp.), Alaska (hb. Dep. Agr.), Vancouver Isl. 

 (Macoun, 1887), Oregon (Hall, 1871, 442; Howell, 1882), 

 Charlotte, Vt. (Pringle, 1877, 1879), Penn Yan, N. Y. 

 ( Wright), and Brookfield, Pa. ( Canby, 1862). Plate 16. 



Lapathum. Hermaphrodite or andro-monoecious: inner segments 

 of perianth (valves) commonly reticulated, becoming round or elongated 

 and much larger than the achene : leaves only exceptionally acid, never 

 hastate : inflorescence with stouter sometimes leafy branches. Peren- 

 nial except H. persicarioides and R. bucephalophorus. 

 * Valves at most very minutely erose or low-denticulate. 

 -t- Valves very large (15 to 50 mm. long), mostly rosy, round or broadly 

 ovate, deeply cordate, without callosities : whorls rather remote 

 but overlapping in fruit : outer sepals at length reflexed : stipular 

 sheaths very large and loose. 



5. K. VENOSDS, Pursh. A span to mostly about a foot 

 high (from deep-seated thin roots?), branching from most 

 of the axils and spreading, glabrous; leaves firm, not wavy, 

 at most 5x10 cm. elliptical or elliptical-ovate, abruptly 

 acute at both ends; inflorescence nearly simple, leafless, 

 the short zigzag branches divergent; pedicels rather stout, 

 about as long as the fruit, tumidly jointed below the middle ; 

 valves rather firm, orbicular or broader than long, 20 to 

 50 mm. in diameter, the sinus often closed, emarginate to 

 shortly blunt acuminate; achene 4x7 mm. Fl. ii. (1814), 

 733 ; Meisner, DC. Prod. xiv. Dry sandy soil in the plains 



