ORDER 102. POLYGONACE^E. 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. J 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. RITMEX, L. DOCK. SORREL. Calyx of 6 sepals nearly distinct, 

 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 

 outer herbaceous, reflexed in fruit ; stamens 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. 



LAPATHUiM". Flowers all or mostly perfect. Valves bearing grains on the tack. (*) 



* 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 subcordatc Nos. 7, 3 



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



ACETOSA. Flowers dioecious. Valves grainless. Leaves acid (hastate) Nos.12, 13 



1 R. crispus L. YELLOW DOCK. Lvs. lanceolate, waved, acute, the lower oblong, 

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

 bearing a grain. if 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 largo 

 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-lanceolate, acute at each end; 

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

 close whorls; pedicels elongated, thickened, upwards. If 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 7 to 10" long, deflexed. Jn. (R. Brittanicus L. ? fide Gray.) 



3 R. Hydrolapathum Hudson, p. AMERICANA Gray. GREAT WATER DOCK. 

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

 late-crenulate, all acute or attenuate at base, petiolate ; panicle compound, at length 

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

 2f 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 mid vein. Pedi- 

 cels in fruit 5 to 6" long, twice longer than the calyx.. (R. aquaticus Smith.) 



4 R. Floridanus Meisn. Lvs. long-lanceolate, acuto and unequally narrowed at 

 loth ends, flat ; panicle, leafless above, racemes at length dense ; pedicels twico 

 longer than the fruiting calyx ; valves broadly ovate-deltoid, bluntly acuminate, all 

 grain-bearing. Fla. (Rugel apud Meisner.) Pedicels 3 to 5" long. 



5 R. altfssimus. PEACH-LEAVED DOCK. Glabrous, tall, erect; Ivs. flat, thick, 

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

 somewhat secund, leafless or the lowest verticil axillary ; fls. all ; valves larger, 

 broad-cordate, one graniferous, one abortively so, and the third naked. If Marshy 

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

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

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

 than the valves. Jn. 



6 R. salicifolius Weinm. /?. BIGELOVII. PALE DOCK. Lvs. thin, wavy at 

 edge, attenuate-acuto 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 than 

 the grains. Sea coast, Mass, and Can. Sts. terete, slightly furrowed, 2 to 3f 

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



7 R. conglomerates Murr. Lvs. ovate or oblong, base rounded or cordate, the 

 upper lanceolate, attenuate-acuto at each end, margins crispatc ; panicle somewhat 



