Flowers greenish-brown or reddish-brown, at or near the ground, with inferior 6-celled ovary.

1a. Leaves alternate, on the stem; flowers on a basal scaly branch (1-4 dm. high; summer) =Virginia Snakeroot, Aristolochia serpentaria.=

1b. Leaves a single basal pair, bearing 1 short-stalked flower between them (spring) (Wild Ginger) --2.

2a. Lobes of the perianth ending in a tubular portion 5-8 mm. long =Wild Ginger, Asarum canadense.=

2b. Lobes of the perianth ending in a tubular portion over 1 cm.

long =Wild Ginger, Asarum canadense var. ac.u.minatum.=

2c. Lobes of the perianth triangular, not tubular at the end =Wild Ginger, Asarum canadense var. reflexum.=

POLYGONACEAE, the Buckwheat Family

Herbs with alternate entire leaves, stipules surrounding the stem above the base of each leaf, and small green, white or pink flowers without petals.

1a. Erect or ascending or prostrate or floating plants --2.

1b. Scrambling or climbing plants, clinging by sharp recurved p.r.i.c.kles on the 4-angled stems (flowers greenish or pink, summer) (Tear-thumb) --32.

1c. Twining vines (flowers white or greenish, summer) --33.

2a. Sepals 6, the 3 inner ones enlarging in fruit and surrounding the achenes; flowers in panicles --3.

2b. Sepals 4 or 5 (occasional flowers may be found with 6 sepals, but the flowers are not in panicles) (summer) --13.

3a. Leaves arrow-shape or halberd-shape, with 2 basal lobes (Sorrel) --4.

3b. Leaves without basal lobes (Dock) --5.

4a. Leaves halberd-shape, the basal lobes directed sidewise =Red Sorrel, Rumex acetosella.=

4b. Leaves arrow-shape, the basal lobes directed backward =Green Sorrel, Rumex acetosa.=

5a. The projecting wings of the fruiting calyx (known as valves) with sharp slender teeth =Bitter Dock, Rumex obtusifolius.=

5b. Valves entire or finely dentate, but without sharp slender teeth --6.

6a. Pedicels straight, thickened toward the end, all regularly deflexed, 3-4 times longer than the fruiting calyx =Swamp Dock, Rumex verticillatus.=

6b. Pedicels 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 mexica.n.u.s.=

10a. Valves oblong =b.l.o.o.d.y 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 cl.u.s.ters; 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 sh.o.r.es =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 er.e.c.t.u.m.=

18a. Leaves broadly triangular (3-7 dm. high; flowers white) =Buckwheat, f.a.gopyrum esculentum.=

18b. Leaves from linear to ovate or oblong --19.

19a. Sepals 4; flowers in very long and slender spike-like racemes (4-10 dm. high) =Knotweed, Polygonum virginianum.=

19b. Sepals 5; flowers in spikes or racemes --20.