ORDER 104. POLYGONACE^E. 281 



4. RHEUM, L. RHUBARB. Calyx colored, 6-sepalled, persistent, bta 

 y. Sty. 3, very short, spreading, stig. nmltifid, reflexed. Ach. 3-augled, 

 the angles margined. 11 Flowers fasciculate in racemous panicles. 

 R. RHAr6NTicuM L. Pie-plant. Leaves smooth, cordate-ovate, very large (1 2f), 



the petioles juicy and pleasantly acid, of equal length ; stems nollow, 3 4f, panicle? 



bursting from large white bracts. Siberia. 



6. RUMEX, L. DOCK. SORREL. Calyx of 6 sepals nearly distinct. 

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

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

 green. Sta. 6. Styles 3, short, stigmas penicillate-fringed. Ach. and seed 

 3-angled, embryo lateral. Weed-like herbs with small, greenish flowers 

 often whorled, in racemes or panicles. May July. (See Addenda.) 

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

 Sorrels. Flowers dioecious. Valves grainless. Leaves acid (hastate; Nos. 11, IS 



* Valves entire, or merely angular. . .(a) 



* Valves conspicuously toothed on each side near the base Nos, 8 1C 



a Pedicels in fruit 2 5 times longer than the subcordak vsives Nos. 1 8 



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



b Leaves flat, all tapering to both ends Nos. 4, 



b Leaves wavy, the lower cordate or subcordate Nos. 6, 7 



1 R. crlspus L. Yellow D. Root fusiform, yellow ; Ivs. lanceolate, wavy, acute, the 



lower oblong, subcordate ; ped. twice longer than calyx ; valves broad -ovate, cordaie. 

 each bearing a grain ; rac. long, some leafy, it Fields. 2 31. Europe. 



2 R. verticlllatus L. Water D. Leaves acute at each end, lance-oblong ; rac. leaf 



less, dense ; ped. 7 9" long, deflexed ; valves broad-ovate, eacn beating a large grain. 

 U In muddy places. 2f. Whorls 10-30-flowered. 



3 R. Hydrolapatlitim Huds. Great Water D. p. orbicululu*. lal, \$ 5f); Ive. 



lance-obi., acute both ways, erose-crenulate, the lower very long; pin. naked, dense- 

 ped. 5 6" ; valves round-ovate, obtuse, all grain-bearing. n Pools, M. and N. 

 y. fi'/or/dani/*. Valves deltoid-ovate, obtusely-pointed. Fla. 



4 R. altissimus Wood. Peach-leaved D. Tall (3 6f); leaves entire, lance-ellipti- 



cal, acute both way* ; rac. leafless, panicled, slender; valves broadly subcordate. one 

 of them grain-bearing, one obscurely so. and one naked. 1\. Wet, M. and W. (R. 

 Uritannicus Meisn. nee Linn, who says "valves all grain-bearing.") 



5 R. sallcifolius Weinm. Pale D. Lve. lin. -lanceolate, atteuuate-acute both ways ; 



pan. leafy at base ; ped. very short ; valves all grain-bearing:, y Coast, N-E. 3f. 



R. conglomerating Mnrr. Lvs. oblong to lanceolate, lower subcordate ; whorl? 



mostly axillary ; valves oblong ovate, all grain-bearing, if Wet. N. Z 3t. 



1 R. sanguiiieus L. Lvs. as in No. 6, mostly with red veins; pan. leafy at base, 



whorls distant ; valves oblong-obovate, one or two grain-bearing, u Fields. 



8 R. obtusifolius L. Lower leaves ovate-cordate, obtuse, upper narrow, acute ; 



panicle leafy, whorls distant ; valves hastate-ovate, one chiefly grain -bearing, all with 

 some bristle-shaped lateral teeth, n Fields, &c. 2 3f. Europe. 



9 R. m i rttimiiM L. Golden D. Low (If); leaves lance-linear, the lowest cordate, 



wavy ; whorls crowded ; valves rhomb-ovate, pointed, each with 4 lateral awns and 

 large grain, yellowish, (i) Brackish waters, Mass, to Car. 



10 R. pulclier L. Lower Iva. cordate, some fiddle-shaped, upper lanceolate ; whurle 

 distant, leafy ; valves strongly toothed, unequally grain-bearing S. 



11 R. Acetosella L. Sheep Sorrel. Leaves oblanceolate, the base lobes conspicu- 

 ous ; valves not increasing in fruit. A common weed. 6' If 



12 R. liastulatus Baldw. Leaves with small auricles or none, glaucous ; valves in 

 creasing to round-cordate in fruit : ped. iointod. Mo. to Ga. . rare. 



