876 POLYGONACEvE. (BUCKWHEAT FAMILY.) 



1. F. ESCULENTUM, Mcench. (BUCKWHEAT.) Smoothish; flower with 8 

 honey-bearing yellow-glands interposed between the stamens ; the fruit acute 

 and entire. (Polygonum Fagopyrum, L.) Old fields, remaining as a weed 

 where the plant has been cultivated, and escaping into copses. June -Sept. 

 (Adv. from Eu.) 



3. OXYRIA, 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, ses- 

 sile, tufted. Achenium lenticular, thin, flat, much larger than the calyx, sur- 

 rounded by a broad and veiny wing. Seed flattened in the opposite direction 

 from the wing. Embryo straight, occupying 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 greenish flowers clustered 

 in panicled racemes on a slender scape. (Name from ovs, sour, in allusion to 

 the acid flavor of the leaves, similar to that of Sorrel.) 



1. O. cligyiia, Campd. Leaves all round-kidney-form, usually notched 

 at the end ; fruit orbicular. Alpine region of White Mountains, New Hamp- 

 shire, Oakes, &c., and high northward. (Eu.) 



4. RUM EX, L. DOCK. SORREL. 



Calyx of 6 sepals ; the 3 outer herbaceous, sometimes united at the base, 

 spreading in fruit; the 3 inner (called valves) larger, somewhat colored, increas- 

 ing after flowering and convergent over the 3-angled achenium, veiny, often 

 bearing a grain-like tubercle on the outer surface. Stamens 6. Styles 3 : stig- 

 mas tufted. Embryo slightly curved, lying along one side of the albumen, 

 slender. Coarse herbs, with small and homely (mostly green) flowers, which 

 are crowded and commonly whorled in panicled racemes ; the petioles some- 

 what sheathing at the base. (The ancient Latin name of these plants; of un- 

 known etymology.) 



$ 1 . LAPATHUM, Tourn. Flowers perfect, or nionozciously polygamous : styles 



free : herbage bitter. 



* Leaves all lanceolate and acute at both ends, flat, smooth : valves of the fruiting 

 calyx entire, or nearly so, not awn-bearing : root perennial. 



1. R. vei'ticillatus, L. (SWAMP DOCK.) Racemes nearly leafless, 

 elongated, the flowers in crowded whorls ; fruit-bearing pedicels slender, dub- 

 shaped, abruptly reflexed, 3 4 times longer than the fruiting calyx ; the valves dilated- 

 rhoniboid, obtusely somewhat pointed, strongly rugose-reticulated, each bearing a very 

 large grain, from to the width of the valve. Wet swamps and ditches ; 

 common. June, July. Stem 2 - 4 high, branched above, Avith pale green, 

 willow-like, thickish, wholly entire leaves ; the lowest ones, more or less 

 cordate at the base. 



2. R. Kritniiiiicn, L. (TALL DOCK.) Racemes spike-like and 

 panicled, nearly leafless (3 -6 high) ; whorls crowded; pedicels nodding, rather 

 shorter than the fruiting calyx ; the valves round-heart-shaped, obtuse, thin, 1 - 3 of 



