C04 Order 102.— POLYGONACEuE. 



albuminous, with a straight or curved inverted embryo. IUust in Figs. 80, 375, 

 407, 40S, 409, 413, 607. 103, 112. 



Genera 33, species C90 (Meisner) widely diffused in all lands, but most abundant in the tem- 

 perate zones. 



Properties. — The roots of these plants are nauseous and purgative. Rhubarb of the shops is 

 the root of Itheum paluiatum 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, arc- well-known 

 articles of food. 



TRIBES AND GENERA. 



1. ERIOGONE.E. Flowers in dense, involucrate umbels, Ochrem Euiogonttm. 1 



II. POLYGONE-E. Flowers not involucrate. Ochresc present, (a) 



a Calyx 4-partcd, regular. Stamens C. Styles 2. Achcnia winged Oxyma. 2 



a Calyx C-parted. Stamens 9. Sepals all similar, short Enr.u.M. 8 



a Calyx C-parted. Stamens 0. Sepals 3, inner increasing, tuberculate Kujiex. 4 



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



b Sepals, the 3 inner fimbriate-pectinate. Pedicels solitary Titysant.lla. 6 



b Sepals entire, — 3, closed on the achenia, or all open. Pedicels solitary. Polygon i:ll a. C 

 — all closed on the achenium. Pedicels usually fascicled .. Polygonum. 7 

 — all open. Nectaries 8. Pedicels fascicled in the bract. ..Fagopyuum. 8 



1. ERIOG'OHUM, Mx. (Gr. eptov, avooI, yovv, knee ; being woolly 

 at the joints, etc.) Flowers many in each common 5-toothcd involucre ; 

 oalyx deeply 5-cleft ; stamens ; styles 3 ; achenia 3-emglcd 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 umbel- 

 late inflorescence. Invol. solitary or capitate. Pedicels within the in- 

 vol. 1-flowcred. 



1 E. tomentcsum Mx. Lower lvs. crowded, spatulate, obovato or oblong, po- 

 tiolatc, beneath rusty white, tomentous, veins tawny red ; flowering branches 

 several times forked ; invol. solitary, campanulate, sessile, 5-toothed, loose-flow- 

 ered; cal. colored, funnel-form. — If. 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 tho same color outside. Jn. Aug. 



2 E. longifolium Nutt. Lower lvs. crowded, oblong-linear, with a long, attenu- 

 ated base, beneath white-tomentous, upper lvs. scattered ; panicle ample, several 

 1 imes forked ; bracts minute ; invol. solitary, campanulate, pedunculate many- 

 flowered ; cal. green, woolly. — Fla. to Ark. St. 2 to 4f high. 



2. OXYR'IA, It. Br. Mountain Sorrel. (Gr. o^vc;, acid ; in allu- 

 sion to the qualities of its leaves.) Calyx herbaceous, 4-scpaled, the 2 

 inner sepals erect, larger, the 2 outer reflexed ; achenium lens-shaped, 

 thin, girt with a broad, membranous wing; stamens 0, equal ; stigmas 



2, sessile, penicillatc. — 2£ Low, nearly acaulescent, alpine plants. 



O. roniformin Hook. Radical lvs. reniform, on long petioles ; outer sepals ob- 

 long, half as long as tho inner, valvular sepals ; fruit orbicular. — Found on tho 

 .summits of tho White Mts., in moist ravines; and N. to tho Arc. Sea. The plant 

 i3 acid to tho taste, like Rumex acetosus. Stem 3 — 4' in height, nearly leafless, 

 racemed or subpaniculate. Jn. (Rumerc digynus L.) 



3. RHE V UM, L. Rhubarb. (IZha, the river Volga, on whose banks 

 the plants are said to be native.) Calyx colored, G-scpalcd, persistent ; 

 stamens 9 ; styles 3, very short, spreading ; stigmas multifid, reflexed ; 

 achenia 3-anglcd, the angles margined. — 2X Fls. fasciculate in racemous 

 panicles. 



R. Rhaponticum L Garden Riiudakb or. Pie-plant. Lvs. ample, 

 smooth, cordate-ovate, obtuse ; petioles channeled above, rounded at tho edges. — 

 Gardens. Stem stout and fleshy, 3 — 4f high, hollow, with large, sheathing sti- 

 pules at the joints. Leaves very kirge, 1 — 21' long, § as wide, en petioles of 



