604 ORDER 102. POLYGONACE^E. 



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 tem- 

 perate zones. 



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

 the root of liheum palmatum and other species, native of Tartary. But the leaves and sbtlfa 

 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, aro well-known 

 articles of food. 



TRIBES AND GEXERA. 



1. ERIOGONEJ3. Flowers in dense, involucrate umbels, Ochrese EEIOGONUM. 1 



II. POLYGONE^E. Flowers not involucrate. Ochrese present, (a) 



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



a Calyx 6-parted. Stamens 9. Sepals all similar, short EIJF.UM. 3 



a Calyx 6-partcd. Stamens 6. Sepals 8, inner increasing, tuberculate KUAIEX. 4 



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



b Sepals, the 3 inner fiinbriate-pectinate. Pedicels solitary TITYSANELLA. 5 



b Sepals entire, 3, closed on the achcnia, or all open. Pedicels solitary. POLYGONELLA. 6 

 nil closed on the achenium. Pedicels usually fascicled.. POLYGOXUM. 7 

 all open. Nectaries 8. Pedicels fascicled in the bract. . .FACOPYKPM. 8 



1. ERIOG'ONUM, MX. (Gr. tptov, wool, yovv, 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 umbel- 

 late inflorescence. In vol. solitary or capitate. Pedicels within the in- 

 vol. 1-flowered. 



1 E. tomentosum MX. Lower Ivs. 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-flow- 

 ered; cal colored, funnel-form. U Sandy hills, S. Car. to Fla., frequent. St. 1 

 to 3f high. Lvs. 2 to 3' long, those of the stem much smaller. Pis. 3 to 4" long, 

 cream-white, with wool of the same color outside. Jn. Aug. 



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

 ated base, beneath white-tomentous, upper Ivs. 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. o|f, acid ; in allu- 

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

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

 thin, girt with a broad, membranous wing ; stamens 6, equal ; stigmas 



2, sessile, penicillate. 2 Low, nearly acaulescent, alpine plants. 



O. reniformia Hook. Radical Ivs. reniform, on long petioles ; outer sepals ob- 

 long, 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 subpaniculatc. Jn. (Rumex digynus L.) 



3. RHE V UM, L. RHUBARB. (Rha, the river Volga, on whose banks 

 the plants arc 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. 2 Fls. fasciculate in racemotis 

 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 tho joints. Loaves very large, 1 2f long, f as wide, on petioles of 



