ORDER 104. POLYGONACE^E. 281 



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

 9. Sty. 3, very short, spreading, stig. multifid, reflexed. Ach. 3-angled, 

 the angles margined. U Flowers fasciculate in racemous panicles. 



R. RHAFONTICUM 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. 



5. RUMEX, L. DOCK. SORREL. 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 outer 

 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 grain:? on the back. . . (*) 



Sorrels. Flowers dioecious. Valves grainless. Leaves acid (^hastate).. ..Nos. 11, 12 



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



* Valves conspicuously toothed on each side near the base Nos, 810 



a Pedicels in Iruit 2 5 times longer than the subcordate valves Nos. 1 3 



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



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



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



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



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

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



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



less, dense ; ped. 79" long, deflexed ; valves broad-ovate, each bearing a large grain. 

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



3 R. Ilydrolapatlmm Huds. Great Water D. p. orbictdiitu*. Tali <3 5f) ; Ivs. 



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

 ped. 5 6" ; valves round-ovate, obtuse, all grain-bearing. 2f Pools, M. and N. 

 y. floridanust Valves deltoid-ovate, obtusely-pointed. Fla. 



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



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

 of them grain-bearing, one obscurely so, and one naked. 2J. Wet, M. and W. (R. 

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



5 R. sallcifollus Weinm. Pale D. Lvs. lin.-lanceolate, atteiiuate-acute both ways ; 



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



*t R. conglomeratus Murr. Lvs. oblong to lanceolate, lower subcordate ; whorls 



mostly axillary ; valves oblong-ovate, all grain-bearing, y. Wet. N. 2 3f. 



7 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. 7i Fields. 



8 R. obtuslfolius 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, li Fields, &c. 2 3f. Europe. 



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



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

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



10 R. pulclier L. Lower Ivs. cordate, some fiddle-shaped, upper lanceolate ; whorla 

 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 Balclw. Leaves with small auricles or none, glaucous ; valves in- 

 creasing to round-cordate in fruit : ped. jointed. Mo. to Ga. . tare. 



