, Ordeb 102.— POLYGONACE^. 605 



nearly the same length. Panicle terminal, at first enclosed in a white, membran- 

 ous bract which at length bursts, disclosing innumerable greenish-white flowers. 

 May. t 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, Soreel. Calyx of 6 sepals nearly distinct, 

 the 3 inner (valves) larger, petaloid, connivent over the achenium, 1 or 

 more of them usually bearing a tubercle or grain on the back, the 3 

 ooter herbaceous, reflexed in fruit ; slamens 6 ; styles 3, short ; stigmas 

 penicillate-fringed ; achenium and seed 3-angled, embryo lateral. — 

 weed-like herbs with small, greenish fls. in racemes or panicles. 



§ LAPATHUM. I'lowers 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. 8,4 



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 subcordate Nos. 7, 8 



* Valves conspicuously toothed on each side near the base Nos. 9 — 11 



§ ACETOSA. riowers diojceous. Valves grainless. Leaves acid (hastate) Nos.l2, 13 



1 R. ciispus L. Yellow Dock. Lvs. lanceolate, waved, acute, the lower oblong, 

 subcordate; pedicels twice longer than calyx; valves broad-ovate, cordate, each 

 bearing a grain. — 2f Can. and IJ. 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. Plowers 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. Wateb Dock. I/us. oblong-lanceolate, acute at each end ; 

 valves entire, broad-ovate, each bearing a grain ; rao. leafless, with flowers in 

 close whorls; pedicels elongated, thickened, wpwards. — % 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.. Pedi- 

 cels 1 to 10" long, deflexed. Jn. (R. Brittanicus L. ? fide Gray.) 



3 R. Hydrolap^thum Hudson. (3. Americana Gray. Great Water Dock. 

 Lvs. lanceolate, acuminate, lower lance-oblong, very long, upper minutely undu- 

 laie-crenulate, all acute or attenuate at base, petiolato ; panicle compound, at length 

 naked ; verticils at first distinct ; valves rowndish-ovate, obtuse, all grain-bearing. — 

 4 Northern U. S. Ponds and ditches. St. 3 to 5f high. Lvs. somewhat glau- 

 cous, lower very large, 1 to 2f long, 2 to 5' wide, with a stout midveiu. Pedi- 

 cels in fi'uit 5 to 6" long, twice longer than the calyx. (E. aquaticus Smith.) 



4 R. Florid^uus Meisn. Lvs. long-lanceolate, acuto and unequally ncurrowed at 

 both ends, flat ; panicle, leafless above, racemes at length dense ; pedicels twice 

 longer than the fruiting calyx ; vaXves broadly ovate-deltoid, bluntly acuminate, aU 



- gpsiin-bearing. — Pla. (Rugel apud Meisner.) Pedicels 3 to 5" long. 



5 R. altissimus. Peach-lbaved Dock. Glabrous, tall, erect; lvs. flat, thick, 

 linear-elliptic, entire, petiolate, tapering to each end ; rac. slender, paniculate, 

 somewhat secund, leafless or the lowest vertioU axillary ; fls. all ^ ; valves la/rger, 

 broad-cordate, one graniferous, one abortively so, and the third tuiked. — y Marshy 

 prairies and borders of streams, Mid. and W. States. A very showy Eumex, 

 3 — 6f high, slightly branched above. Leaves 3 — 5' by i — 1', somewhat acumi- 

 nate, broadest in the middle. Verticils approximate, pedicels reflexed, not longer 

 than the valves. Jn. 



6 R. salioifdlius "Weinm. /?. Eigelovu. Pale Dock. Lvs. thin, wavy at 

 edge, attenuate-acute at each end, linear-lanceolate, petiolate; panicle simple, 

 leafy at base, racemes spicate, loose and interrupted below ; pedicels much shorter 

 than the fruiting calyx ; valves all grain-bearing, ovate-oblong, scarcely longer titan 

 the grains. — Sea coast, Mass. and Can. Sts. terete, slightly furrowed, 2 to 31 

 high. Lvs. 4 to 7' long. Grains unequal, large, white. Jn. (E. pallidus Bw.) 



7 R. conglomer^tus Murr. Lvs. ovate or oblong, base rounded or cordate, the 

 upper lanceolate, attenuate-acute at each end, margins crispate ; panicle somewhat 



