edicels slender, flexuous, spreading --7.

7a. Leaves flat or nearly so --8.

7b. Leaves with strongly crisped or wavy-curled margins; plants usually
of cultivated grounds or waste places (5-10 dm., summer) --12.

8a. With grain-like tubercles on all 3 valves of the fruit --9.

8b. With grain-like tubercles on only one valve, or entirely
lacking --10.

9a. Valves broadly cordate, finely toothed
=Water Dock, Rumex brittanica.=

9b. Valves triangular-ovate, entire or nearly so
=Dock, Rumex mexicanus.=

10a. Valves oblong =Bloody Dock, Rumex sanguineus.=

10b. Valves broadly heart-shape --11.

11a. Grain-like tubercle less than half as long as the valve
=Patience Dock, Rumex patientia.=

11b. Grain-like tubercle more than half as long as the valve
=Tall Dock, Rumex altissimus.=

12a. The grain-like tubercle on the valves of the fruit broadly
ellipsoid, with rounded apex =Sour Dock, Rumex crispus.=

12b. Tubercle ovoid with tapering apex
=Sour Dock, Rumex elongatus.=

13a. Flowers inconspicuous, in small axillary clusters; leaves jointed
at the base (Knotweed) --14.

13b. Flowers more or less conspicuous, in obvious spikes or racemes
which terminate the stems or branches, or arise from the axils of
the upper leaves --18.

14a. Leaves sharply folded lengthwise (1-4 dm. tall)
=Knotweed, Polygonum tenue.=

14b. Leaves flat or nearly so --15.

15a. The small sepals pink or white at the margin (stems prostrate or
ascending) --16.

15b. Sepals greenish or yellowish throughout (stems erect or ascending)
--17.

16a. Leaves thin; common weed of dooryards and gardens
=Knotweed, Polygonum aviculare.=

16b. Leaves thick and fleshy; a plant of sandy shores
=Knotweed, Polygonum aviculare var. littorale.=

17a. Leaves narrowly lanceolate or linear-oblong; rare species
=Knotweed, Polygonum ramosissimum.=

17b. Leaves broadly oblong, oval, or elliptical; common weed of yards
and gardens =Knotweed, Polygonum erectum.=