POLYGONACE^. (BUCKWHEAT FAMILY.) 437 



triangular. Embryo straight and axile, with foliaceous cotyledons. — Annu- 

 als or perennials, with radical or alternate or whorled entire leaves, without 

 stipules. (Name from ^piou, icool , and yovv, knee.) 



1. E. annuum, Nutt. Annual, erect, leafy, naked above, 2° bigli, white- 

 floccose-tomentose throughout; leaves oblong-lanceolate, acute at both ends, 

 sliort-petiolate, flat ; bracts small, triangular ; involucres numerous in terminal 

 cymes, turbinate, shortly pedicelled, 1 - 1 h" long, very tomentose ; flowers 

 white, the outer sepals oblong-obovate, 1" long or less. — Central Kan. to CoL. 

 and southward. 



2. OXYRIA, Hill. Mountain Sorrel. 



Calyx herbaceous, of 4 sepals; the outer smaller and spreading, the inner 

 broader and erect (but unchanged) in fruit. Stamens 6. Stigmas 2, sessile, 

 tufted. Achene lenticular, thin, flat, much larger than the calyx, surrounded 

 by a broad veiny wing. Seed flattened contrary to the wing. Embryo straight, 

 in the centre of the albumen, slender. — Low alpine perennial, with round- 

 kidney-form and long-petioled leaves chiefly from the root, obliquely truncate 

 sheaths, and small greenish flower.^ clu.stered in panicled racemes on a slender 

 scape. (Xame from oi^vs, sour, in allusion to the acid leaves.) 



1. O. digyna, Hill. Leaves all round-kidney-form, usually notched at 

 the end; fruit orbicular. — Alpine region of the White Mts., and far north 

 and westward. (Eu.) 



3. RUM EX, L. Dock. Sorrel. 



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

 ing in fruit ; the .3 inner larger, somewhat colored, enlarged after flowering 

 (in fruit called vah-es) and convergent over the 3-angled achene, veiny, often 

 bearing a grain-like tubercle on the back. Stamens 6. Styles 3 ; stigmas 

 tufted. Embryo slightly curved, lying along one side of tlie albumen, slender. 

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

 crowded and commonly whorled in panicled racemes ; the petioles somewhat 

 sheathing at base. (The ancient Latin name ; of unknown etymology.) 

 § 1. LAFATHUM. (Dock.) Flowers perfect or monoeciously pol ijgunious ; 

 herbage not sour or scarce! i/ so ; none of the leaves halberd-shaped. {Flower- 

 ing through the summer.) 



* Perennials, 1-7° high, mostlg with fusiform roots; valves not bearing bristles.. 



H- Valves {large, 3" broad or more, thin) all naked or one icith a small grain. 



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

 oblong and lanceolate leaves (broadest above the base), those from the root 2- 

 3° long, and one of the heart-shaped nearly or quite entire valves (3'' broad) 

 bearing a small grain, or its midrib thickened at base. — N. Eng. and N. Y. 

 (Adv. from Eu.) 



1. R. venosus, Pursh. Stems from running rootstocks, erect (1° high 

 or less), with consjjicuous dilated stipules; leaves on short but rather .slender 

 petioles, ovate or oblong to lanceolate (3-6' long), acute or acuminate, only 

 the lowest obtuse at l)ase ; panicle nearly sessile, short, dense in fruit; valves 

 entire, glandless, broadly cordate with a deep sinus, 9 - 12" in diameter, briglit 

 rose-color. — Sask. to central Mo. and Kan., and wostwnrd. 



