1 Leaf blades of well-developed leaves (at least) hastate or sagittate; plants dioecious (rarely polygamo-monoecious), the flowers mostly unisexual; fresh foliage pleasantly acid to taste.

1 Leaf blades not hastate or sagittate; plants synoecious (rarely with some dioecious or polygamo-monoecious individuals), the flowers normally bisexual (sometimes bisexual and unisexual flowers in the same inflorescence); fresh foliage “green” or bitter to taste; [subgenus Rumex].

..2 Leaves primarily cauline; inner tepal margins entire; [subgenus Rumex; section Axillares].

....3 Inner tepals 23-30 mm wide, atleast 20 mm in width, distinctly double-reticulately veined

....3 Inner tepals not (or rarely) exceeding 15 mm in width, singly-reticulately veined (or obscurely veined, if at all).

......4 Pedicels 2.5-5× as long as the inner tepals; pedicel joint (articulation) below the midpoint of the pedicel.

........5 Leaf blades ca. 2× as long as wide; lateral veins of leaves forming angle of ca. 80° to midvein

........5 Leaf blades 3-7 (-10)× as long as wide; lateral veins of leaves forming angle of 40-60° to midvein.

..........6 Leaf blades 3-5 (-6)× as long as wide; coriaceous and usually somewhat fleshy; inflorescences dense (interrupted only at base); pedicels 2.5-3× as long as the inner tepals; inner tepals as wide as or wider than long

..........6 Leaf blades 5-7 (-10)× as long as wide; thin; inflorescences interrupted in at least the lower half; pedicels 3-5× as long as the inner tepals; inner tepals longer than wide (rarely as long as wide)

......4 Pedicels usually < 2.5× as long as the inner tepals (or shorter than); pedicel joint (articulation) either at the midpoint of the pedicel, or below it.

............ 7 Leaf blades widest toward the apex; leaf apex rounded or obtuse

............ 7 Leaf blades widest at the middle or toward the base; leaf apex acute or attenuate (rarely nearly obtuse).

............ ..8 Leaf blades widest toward the base (proximal 1/3); inner tepals 4.5-6 x 3-4.5 (-6) mm (R. altissimus) or 7-10 x 8-12 mm (R. spiralis)

............ ....9 Base of inner tepals (proximal-most portion) truncate or indistinctly cordate; inner tepals 4.5-6 mm long; plants with vertical rootstock; [widespread in US in a variety of wet habitats]

............ ....9 Base of inner tepals (proximal-most portion) deeply and broadly cordate; inner tepals 7-10 mm long; plants with creeping rhizomes; [sandy and gravelly shores, TX]

............ ..8 Leaf blades widest near the middle; inner tepals (2-) 2.5-4.5 (-5) mm long, (2-) 2.5-4 (-4.5) mm wide.

............ ......10 Inflorescence lax, distinctly interrupted; leaf blades thick and coriaceous, deep green, with veins prominent on the lower surface; leaf apex nearly obtuse; inner sepals 3.5-4.5 (-5) mm long, 3-4 (-4.5) mm wide

............ ......10 Inflorescence dense, interrupted only toward its base; leaf blades light or yellowish green, the veins on the lower surface not noticeably prominent; leaf apex acute; inner sepals (2-) 2.5-3.5 (-3.8) mm long, (2-) 2.5-3 (-3.5) mm wide

..2 Leaves basally disposed, the largest and best developed in a basal rosette (these sometimes withering at maturity, especially in annual species); inner tepal margins entire or variously dentate; [subgenus Rumex; section Rumex].

............ ........11 Inner tepal margins entire, indistinctly erose, or (rarely) minutely denticulate (the teeth then < 0.2 mm long).

............ ..........12 Inner tepals ca. 2× as long as wide, margins entire, largest tubercle almost as wide as the inner tepal.

............ ............ 13 Tubercles 3, equal or nearly so in size; inflorescence leafy through at least 2/3 of its length; pedicels 1.4 (-5) mm long

............ ............ 13 Tubercles 1 (or if 3, then one much larger than the other 2); inflorescence leafy only in basal 1/3 or less of its length; pedicels (2-) 4-6 (-8) mm long

............ ..........12 Inner tepals ca. 1-1.5× as long as wide, margins entire or denticulate, largest tubercle much narrower than the inner tepal (or tubercle absent in R. hymenosepalus).

............ ............ ..14 Tubercles 3, equal or nearly so in size; leaf blade >8× as long as wide, 20-55 (-70) cm long, 2-7 cm wide

............ ............ ..14 Tubercles absent, 1 or 2-3 (if 2-3, then one much larger than the other 1 or 2 tubercles); leaf blade <6× as long as wide, 15-45 (-50) cm long, 2-15 cm wide.

............ ............ ....15 Plants with distinctly tuberous roots and short lateral rhizomes; leaves whitish or silvery-white; [native, deep sands, e. TX westward; subsection Hymenosepali]

............ ............ ....15 Plants with fusiform, vertical rootstocks; leaves green; [non-native, widespread in disturbed habitats of e. and w. US]

............ ............ ......16 Leaf blade 30-45 (-50) cm long, 10-15 cm wide; the margins plane or weakly undulate; inner tepals (5-) 5.5-8 (-10) mm long; tubercles normally 1 (rarely 2-3)

............ ........11 Inner tepal margins prominently dentate, at least some of the teeth > 0.3 mm long.

............ ............ ........17 Inner tepals (not including the teeth) orbiculate-ovate to deltate, as wide as long

............ ............ ........17 Inner tepals (not including the teeth) ovate-triangular, triangular, or narrowly-triangular, evidently longer than wide.

............ ............ ..........18 Inner tepals with 3-5 strongly hooked teeth on each side

............ ............ ..........18 Inner tepals with straight teeth.

............ ............ ............ 19 Leaf blade > 4× as long as wide; inner tepals (not including the teeth) ca. 2× as long as wide

............ ............ ............ ..20 Bases of leaf blades narrowly cuneate (rarely broadly cuneate); abaxial surface of leaf blades and inflorescence branches glabrous or inconspicuously papillose; tubercle of the inner tepals usually smooth; [non-native of disturbed habitats, NJ northward]

............ ............ ............ ..20 Bases of leaf blades abruptly truncate to slightly cordate (occasionally broadly cuneate); abaxial surface of leaf blades and inflorescence branches papillose-pubescent; tubercle of the inner tepals distinctly reticulate-pitted; [natives in a variety of coastal and inland wetland and riparian habitats, collectively widespread]

............ ............ ............ ....21 Tubercles linear-lanceolate to fusiform with acute to subacute apices, ½ the width of the inner tepals (excluding the marginal teeth), brown to red-brown (on fresh plants); teeth of inner tepal margins 1.5-2.5x as long as inner tepal width; [scattered throughout our area]

............ ............ ............ ....21 Tubercles oblong-ovate with obtuse apices, similar in width to inner tepals (excluding the marginal teeth), cream to white-yellow (on fresh plants); teeth of inner tepal margins ± equal to inner tepal width; [rare, saline-influenced coastal wetlands, Long Island (historical) northward]

............ ............ ............ 19 Leaf blade 2-3× as long as wide; inner tepals (not including the teeth ca. 1.5× as long as wide (sometimes to 2× as long as wide in R. obtusifolius).

............ ............ ............ ......22 Plants perennial; base of leaf blade usually distinctly cordate.

............ ............ ............ ........23 Stems 6-12 (-15) dm tall; leaf blades 20-40 cm long; inflorescence branches normally ascending, making an angle of 30-45° with inflorescence axis; tubercles of the inner sepals smooth

............ ............ ............ ........23 Stems 2-6 (-7) dm tall; leaf blades 4-10 (-15) cm long; inflorescence branches spreading, making an angle of 60-90° with inflorescence axis; tubercles of the inner sepals usually verrucose

............ ............ ............ ......22 Plants annual or biennial; base of leaf blade cuneate (rarely rounded).

............ ............ ............ ..........24 Inner tepals 4-5 (-5.5) mm long; tubercles of the inner sepals verrucose

............ ............ ............ ..........24 Inner tepals 3-4 mm long; tubercles of the inner sepals smooth or minutely punctate