POLYGONACEiE. (BUCKWHEAT FAMILY.) 391 
stamens; fruit twice the length of the calyx, the angles acute and en¬ 
tire. (Polygonum Fagopyrum, L .) — Old fields, remaining as a weed 
where the plant has been cultivated. June - Sept. 
OXYJRIA, Hill. Mountain Sorrel. 
Calyx herbaceous, of 4 sepals; the two outer smaller and 
spreading, the two inner broader and erect (but unchanged) in 
fruit. Stamens 6. Stigmas 2, sessile, tufted. Achenium len¬ 
ticular, thin, flat, much larger than the calyx, surrounded by a 
broad veiny wing. Seed flattened in the opposite direction. Em¬ 
bryo straight, in the centre of the albumen, slender. — Low alpine 
perennials, with round-kidney-form and long-petioled leaves chief¬ 
ly from the root, obliquely truncate sheaths, and small green¬ 
ish flowers clustered in panicled racemes on a slender scape. 
(Name from sour , in allusion to the acid flavor of the leaves, 
like those of Sorrel.) 
1. O, dlgyna, Campd. Leaves all round-kidney-form, usually 
notched at the end j fruit orbicular. (O. reniformis, Hook.) — Alpine 
region of White Mountains, New Hampshire, Oakes , &c. July — 
Scape 3' -10' high. 
RUMEXy L. Dock. Sorrel. 
Calyx of 6 sepals ; the 3 outer herbaceous, somewhat united at 
the base, spreading in fruit; the 3 inner (called valves) larger, 
somewhat colored, increasing and valvately convergent over the 3- 
angled achenium, veiny, often bearing a grain-like tubercle on the 
outer surface. Stamens 6. Styles 3 : stigmas tufted. Embryo 
slightly curved, lying along one side of the albumen, slender.— 
Coarse herbs, with small homely (mostly green) flowers, common¬ 
ly whorled in panicled racemes : petioles somewhat sheathing 
at the base. (The ancient Latin name, of unknown etymology.) 
§ 1. Lapathum, Tourn. — Flowers perfect , or sometimes polyga¬ 
mous : styles free : herbage bitter. 
* Leaves all lanceolate and acute at both ends, flat, smooth: valves of 
the fruiting calyx entire, or rarely obscurely denticulate. 
1. R. verticillatus, L. (Swamp Dock.) Racemes nearly 
leafless, elongated, the flowers in crowded whorls; fruit-bearing pedi- 
cels club-shaped, abruptly reflexed, 3-4 times longer than the fruiting 
calyx ; the valves dilated-rhomboid, obtusely somewhat pointed, strongly 
rugose-reticulated, each bearing a very large grain. — Wet swamps and 
ditches, rather common. June, July. — Stem 2°-4°high, branched 
