Herbs, rarely shrubs, with alternate leaves and mostly sheathing stipules (ochreœ) surrounding the stem above each tumid joint. Flowers mostly perfect. Perianth or calyx 3 to 6-cleft, mostly colored, imbricated in bud and persistent. Stamens 4 to 15, perigynous or free. Ovary 1-celled, free, with a single, erect ovule. Stylet or stigmas 2 or 3. Fruit a 3-angled achenium enclosed in the calyx. Seed erect albuminous, with a straight or curved inverted embryo. Illust. in Figs. 80, 375, 407, 408, 409, 413, 607. 103, 112.

Genera 33, species 690 (Meisner) widely diffused in all lands, but most abundant in the teni-perate zones.

Properties. - The roots of these plants are nauseous and purgative. Rhubarb of the shops la the root of Rheum palmatum and other species, native of. Tartary. But the leaves and stalks of Sorrel, the petioles of Garden Rhubarb, etc, are agreeably tart, and contain oxalic acid; the petioles of the latter, together with the farinaceous seeds of the Buck-wheat, are well-known articles of food.

Tribes And Genera

I.

ERIOGONEae. Flowers in dense, involucrate umbels, Ochreae 0................................

ERIOGONUM.

1

II.

POLYGONEae. Flowers not involucrate. Ocbreae present, (a)

a Calyx 4-parted, regular. Stamens 6. Styles 2. Achenia winged............................

OXYRIA.

2

a Calyx 6-parted. Stamens9. Sepals all similar, short.............................................

RHEUM.

3

a Calyx 6-parted. Stamens 6. Sepals 3, inner increasing, tuberculate.....................

RUMEX.

4

a Calyx 5-parted (irregularly 4-parted in one species), (b)

b Sepals, the 3 inner fimbriate-pectinate. Pedicels solitary...................................

THYSANELLA.

5

b Sepals entire, - 3, closed on the achenia, or all open. Pedicels solitary.

POLYGONELLA.

6

- all closed on the achenium. Pedicels usually fascicled............

Polygonum.

7

- all open. Nectaries S. Pedicels fascicled in the bract............

Fagopyrum.

8

1. ERIOG'ONUM, Mx. (Gr.Tribes And Genera 1486 wool, Tribes And Genera 1487 knee; being woolly at the joints, etc.) Flowers many in each common 5-toothed involucre; calyx deeply 5-cleft; stamens 9; styles 3; achenia 3-angled or 3-lobed; embryo in or near the axis of scanty albumen. - Herbs clothed with dense cottony wool. Lvs. alternate, exstipulate, mostly at the base of the stem, the upper bract-like, often whorled at the forks of the umbellate inflorescence. Invol. solitary or capitate. Pedicels within the in-vol. 1-flowered.

1 E. tomentosum Mx. Lower lvs. crowded, spatulate, obovate or oblong, pe-tiolate, beneath rusty white, tomentous, veins tawny red; flowering branches several times forked; invol. solitary, campanulate, sessile, 5-toothed, loose-flowered; cal. colored, funnel-form. -Tribes And Genera 1488 Sandy hills, S. Car. to Fla., frequent. St. 1 to 3f high. Lvs. 2 to 3' long, those of the stem much smaller. Fls. 3 to 4" long, cream-white, with wool of the same color outside. Jn. Aug.

2 E. longifolium Nutt. Lower lvs. crowded, oblong-linear, with a long, attenuated base, beneath white-tomentous, upper lvs. scattered; panicle ample, several times forked; bracts minute; invol. solitary, campanulate, pedunculate many-flowered; cal. green, woolly. - Fla. to Ark. St. 2 to 4f high.

2. OXYR'IA, R. Br. Mountain Sorrel. (Gr.Tribes And Genera 1489 acid; in allusion to the qualities of its leaves.) Calyx herbaceous, 4-sepaled, the 2 inner sepals erect, larger, the 2 outer reflexed; achenium lens-shaped, thin, girt with a broad, membranous wing; stamens 6, equal; stigmas 2, sessile, penicillate. - Tribes And Genera 1490 Low, nearly acaulcscent, alpine plants.

O. reniformis Hook. Radical lvs. reniform, on long petioles; outer sepals oblong, half as long as the inner, valvular sepals; fruit orbicular. - Found on the summits of the White Mts., in moist ravines; and N. to the Arc. Sea. The plant is acid to the taste, like Rumex acetosus. Stem 3 - 4' in height, nearly leafless, racemed or subpaniculate. Jn. (Rumex digynus L.)

3. RHE'UM, L. Rhubarb. (Rha, the river Volga, on whose banks the plants are said to be native.) Calyx colored, 6-sepaled, persistent; stamens 9; styles 3, very short, spreading; stigmas multifid, reflexed; achenia 3-angled, the angles margined. -Tribes And Genera 1491 Fls. fasciculate in racemous panicles.

R. Rhaponticum L. Garden Rhubarb or Pie-plant. Lvs. ample, smooth, cordate-ovate, obtuse; petioles channeled above, rounded at the edges. - Gardens. Stem stout and fleshy, 3 - 4f high, hollow, with large, sheathing sti-pules at the joints. Leaves very large, 1 - 2f lor.g, 2/3 as wide, en petioles of nearly the same length. Panicle terminal, at first enclosed in a white, membranous bract which at length bursts, disclosing innumerable greenish-white flowers. May. † Siberia. - The large juicy petioles are well-known to the pastry cook. Their agreeable acidity is due to the presence of oxalate of lime.

4. RU'MEX, L. Dock. Sorrel. Calyx of 6 sepals nearly distinct, the 3 inner (valves) larger, petaloid, connivent over the acheniurn, 1 or more of them usually bearing a tubercle or grain on the back, the 3 outer herbaceous, reflexed in fruit; stamens 6; styles 3, short; stigmas penicillate-fringed; acheniurn and seed 3-angled, embryo lateral. - Weed-like herbs with small, greenish fls. in racemes or panicles.

§ LAPATHUM. Flowers all or mostly perfect. Valves bearing grains on the back. (*)

* Valves entire or merely angular, (a)

a Pedicels in fruit 2 to 5 times longer than the sub-cordate valves.................

Nos. 1, 2

a Pedicels in fruit twice longer than rounded or truncate valves......................

Nos. 3, 4

a Pedicels in fruit shorter or not longer than the valves, (b)

b Leaves flat, all tapering to both ends...................................................

Nos. 5, 6

b Leaves wavy, the lower cordate or sub-cordate...................................

Nos. 7, 8

* Valves conspicuously toothed on each side near the base...................................

Nos. 9 - 11

§ ACETOSA. Flowers dioecious. Valves grainless. Leaves acid (hastate).........

Nos.12, 18

1 R. crispus L. Yellow Dock. Lvs. lanceolate, waved, acute, the lower oblong, subcordate; pedicels twice longer than calyx; valves broad-ovate, cordate, each bearing a grain. -Tribes And Genera 1492 Can. and U. S. A weed too common in cultivated grounds, about rubbish, etc., much to the annoyance of the farmer. Stem 2 - 3f high, smooth, channeled, from a yellow, fusiform root. Flowers numerous, in a large panicle, consisting of many racemes of half-whorls, interspersed with leaves. Pedicels 3 to 4" long. Calyx-valves each with a grain on the back. Jn. § Eur. - The root is used in medicine for cutaneous diseases.

2 R. verticillatus L. Water Dock. Lvs. oblong-lanceclate, acute at each end; valves entire, broad-ovate, each bearing a grain; rac. leafless, with flowers in close whorls; pedicels elongated, thickened, upwards. -Tribes And Genera 1493 An aquatic species of muddy situations. Can. and U. S. St. 2f high, with long, tubular sheaths and few branches. Lvs. long, narrow, acute, flat. Whorls 10 to 30-flowered. Pedicels 7 to 10" long, deflexed. Jn. (R. Brittanicus L. ? fide Gray.)