This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Perennial or annual, leafy-stemmed herbs, some species slightly woody, the leaves in some mainly basal. Stem grooved, mostly branched, erect, spreading or creeping. Leaves entire or undulate, flat or crisped, the ocreae usually cylindric, brittle and fugacious, the inflorescence consisting of simple or compound, often panicled racemes. Flowers green, perfect, dioecious, or polygamo-monoecious, whorled, on jointed pedicels. Corolla none. Calyx 6-parted, the 3 outer sepals unchanged in fruit, the 3 inner ones mostly developed into wings, one or all three of which usually bears a callosity (tubercle); wings entire, dentate, or fringed with bristle-like teeth. Stamens 6, included or exserted; iilammts- very short, glabrous. Style 3-parted; stigmas peltate, tufted; achene 3-angled, the angles more or less margined. Embryo curved or nearly straight, borne in one of the faces of the 3-angled seed. [The ancient Latin name.]
About 140 species, of wide geographic distribution. Besides the following, some 15 others occur in the southern and western parts of North America. Type species: Rumex Patientia L.
♦Leaves hastate; flowers dioecious; foliage acid; low species.
Inner sepals not developing wings in fruit; achene granular.
Fruiting inner sepals developing wings; achene smooth.
Basal leaves numerous; wings orbicular-cordate.
Basal leaves few; wings broadly oblong-cordate.
** Leaves not hastate; flowers perfect or polygamo-dioecious; foliage scarcely or not at all acid; ta.l species.
Leaves flat, bright or light green, or glaucescent.
W ings 1/2'- 1 1/2' broad, reddish; no tubercles.
Wings small, not red, bearing tubercles.
Tubercles usually 3.
Pedicels little longer than the wings.
Tubercles broad, nearly or quite as long and often nearly as wide as the wings.
Tubercles narrow, much shorter and narrower than the wings.
Pedicels several times longer than the wings.
Tubercle usually 1; pedicels equalling the wings.
Leaves wavy-margined or crisped, dark green, not glaucescent.
Wings entire, more or less undulate.
Lower leaves narrowed or acuminate at the base.
Lower leaves cordate or rounded at the base.
Tubercles mostly 3.
Inflorescence not leafy; pedicels long.
Inflorescence leafy; pedicels short.
Tubercle 1; inflorescence not leafy; pedicels short.
Wings toothed or fringed.
Lower leaves cordate.
Wings ovate or oblong-ovate; tubercles mostly 2.
Wings hastate or ovate-hastate; tubercle 1.
Lower leaves mostly narrowed at base; wings with 4 spreading bristle-like teeth.