POLYGON ACEM. (BUCKWHEAT FAMILY.) 419 



2. PAGOPYEUM, Tourn. Buckwheat. 



Calyx petal-like, equally 5-parted, withering and nearly unchanged in fruit. 

 Stamens 8. Styles 3: stigmas capitate. Achenium 3-sided, longer than the 

 calyx. Embryo large, in the centre of the albumen, which it divides into 2 parts, 

 with very broad and foliaceous plaited and twisted cotyledons. — Annuals, with 

 triangular-heart-shaped or halberd-shaped leaves, semicylindrical sheaths, and 

 corymbose racemes or panicles of white flowers, often tinged with green or rose- 

 color. (Name, (pnyus, the beech, and nvpos, wheat, from the shape of the grain 

 being that of the beech-nut ; whence also the English name Buckwheat, from* 

 the German 23ttcfje, beech.) 



1. F. esculentum, Moench. (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 

 after cultivation, 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 

 chiefly from the root, obliquely truncate sheaths, and small greenish flowers 

 clustered in panicled racemes on a slender scape. (Name from d£vs, sour, in 

 allusion to the acid leaves, like those of Sorrel. ) 



1 • O. digyna, Campdera. Leaves all round-kidney-form, usually notched 

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

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



4. RUMEX, L. Dock. Sorrel. 



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

 spreading in fruit ; the 3 inner larger, somewhat colored, increasing after flow- 

 ering and convergent over the 3-angled achenium, veiny, often bearing a grain- 

 like tubercle on the back (in fruit called valves). Stamens 6. Styles 3: 

 stigmas tufted. Embry. slightly curved, lying along one side of the albumen, 

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

 are crowded and comiripniy whorled in panicled racemes ; the petioles somewhat 

 sheathing at the base. ' (The ancient Latin name of these plants ; of unknown 

 etymology.) 



§ 1. Dock. Flowers perfect or monceciously polygamous: herbage not sour: none 



of the leaves halberd-shaped. (Flowering through the summer.) 



# Perennials, 2° -7° high: valves not bearing bristles. 



h- Valves (large, 3" broad, thin) all naked or one ivith a small grain. 



1. R. Patientia, L. (Patience Dock.) A very tall species, with ovate- 



oblong and lanceolate leaves, those from the root 2° - 3° long, and one of the 



