1 Shrubs and subshrubs; [TX]; [subgenus Pterochiton].

  2 Shrub or subshrub, 2-10 dm tall; leaves 5-25 mm wide; leaf margin entire or sinuate-dentate to strongly undulate-crisped; leaf tip acute

  2 Shrub, 8-20 dm tall; leaves 3-8 mm wide; leaf margin entire; leaf tip retuse or obtuse

1 Herbs; [collectively widespread].

    3 Leaves white to gray, densely and finely scurfy, especially on the upper surface.

      4 Seeds dimorphic with black seeds 1.5-1.7 mm long and brown seeds 2 mm long; all leaves alternate; [s. TX]

      4 Seeds monomorphic, yellow to brown or reddish-brown; some leaves opposite or subopposite, rarely all alternate; [collectively widespread].

        5 Leaves 2-5 mm long; seeds yellow, 1 mm wide; [coastal TX]

        5 Leaves 5-75 mm long; seeds brown to reddish brown, 1-2 mm wide; [collectively widespread].

          6 Plants annual; stems erect; leaves sessile; [TX]

          6 Plants perennial or annual; stems sprawling to erect; leaves sessile to subsessile or petiolate; [collectively widespread].

             7 Leaves lance-ovate or lanceolate to deltoid or cordate, 5-75 mm wide; [w. and n. TX]

             7 Leaves oblong or oval or rhombic-ovate to lanceolate or elliptic, 1-20 mm wide; [subgenus Obione; section Obione; subsection Arenariae].

               8 Fruiting bracteoles (3.5-) 4.5-7 mm long, 3.5-5.6 mm wide, longer than broad; faces with or without appendages

    3 Leaves usually green on both surfaces, glabrous or sparingly powdery or scurfy; [subgenus Atriplex, section Teutliopsis].

                 9 Fruiting bracteoles not thickened with spongy tissue.

                   10 Fruiting bracteoles ovate to elliptic or orbiculate-cordate

                   10 Fruiting bracteoles never orbiculate-cordate, frequently toothed, usually with lateral angles.

                     11 Radicle of brown seeds basal and spreading; bracts 2.5-3.9 mm wide, 5-13 mm long; plants green or red-tinged throughout; [intact saline or brackish habitats].

                       12 Bracteoles thin throughout, entire or with a single tooth on each margin; black seeds 2.0-2.9 mm; leaves ovate-triangular, lobed or dentate to entire, distal ones lanceolate and entire but with short hastate lobes; plants often tinged with red throughout (stems and leaves)

                       12 Bracteoles typically with well-developed spongy-thickening at base, variously toothed; black seeds rare or lacking, or of various size; leaves all entire or some or all deltoid-hastate with lobes spreading to antrorse and otherwise entire or irregularly toothed; plants usually green-colored, sometimes with moderate to strong red-tinging

                     11 Radicle of brown seeds sub-basal to median and antrorse; bracts 1.5-2.5 mm wide, 3-5 mm long; plants green or rarely with weak red-tinging; [nonsaline ruderal habitats]

                 9 Fruiting bracteoles thickened with spongy tissue, especially toward the base.

                          13 Lower leaves linear or ovate-lanceolate, sometimes toothed and/or with proximal-most lobe largest, but then not triangular, or, if so, then leaves thick textured.

                            14 Leaves linear to lanceolate or oblong, thin, green or slightly scurfy when young; seeds ovoid, not wider than long

                            14 Leaves ovate-lanceolate or linear, or triangular or triangular-hastate, typically thickened and ± scurfy, even in age; seeds ellipsoid, wider than long

                          13 Lower leaves (sometimes all or most) triangular and thin textured.

                              15 Bracteoles short stipitate or sessile; bracteole margins entire to denticulate to laciniate; inflorescences with leafy bracts to the tip, glomerules loose, irregularly spaced; bracteoles thick spongy, margin united to middle; seeds 2.5+ mm wide, usually not distinctly dimorphic, dark brown to black, irregularly biconvex; radicle median, ± antrorse

                              15 Bracteoles sessile; bracteole margins entire to slightly toothed; inflorescences with leafy bracts only at base, glomerules tight, contiguous or irregularly spaced; bracteoles thin to slightly thickened and spongy, margin united only at base; seeds mostly less than 2.5 mm wide, usually distinctly dimorphic, mostly small and glossy black, but also some larger, and dull brown, flattened and disc-shaped; radicle subbasal, obliquely antrorse to spreading