32. Streptanthus squamiformis Goodman, Rhodora 58: 354. 1957. TYPE: United States, Oklahoma, McCurtain Co., slope of pine-oak forest, Beaver’s Bend State Park, 27 Apr. 1952, George J. Goodman 5507 (holotype, OKL; GH!, NY!, UC!).
Herbs, annual, sparsely to densely pubescent or glabrous except for sepals. Stems 1.5–8.5(–11) dm, single, simple or branched above, sparsely to densely hirsute at base, glabrous distally or rarely throughout. Basal leaves not rosulate, petiolate, withered by flowering; middle cauline leaves ovate to oblong or lanceolate, 1–9 x 0.5–3 cm, sessile, amplexicaul, entire or rarely shallowly dentate, glabrous or pubescent along midvein abaxially; upper leaves similar, smaller, glabrous. Racemes ebracteate, dense to lax, without a terminal cluster of sterile flowers; fruiting pedicels divaricate-ascending, straight, glabrous or pubescent, 5–16 mm. Flowers: sepals forming campanulate calyx, purplish, 4–7 mm, not keeled, hirsute with trichomes 0.7–2 mm, both pairs with subapical callosities 1–2.5 mm; petals purple with a dark purple center, 9–17(–20) mm; blade 5–10 x 5–7 mm, not crisped; claw 4–7 mm, narrower than blade; stamens tetradynamous; median filament pairs free, 5–6 mm; lateral pairs 3–4 mm; anthers of all stamens fertile, 1.5–2.8 mm. Fruits 6–14 x 2–3 mm, ascending to suberect, straight, flattened, not torulose; valves glabrous, with a prominent midvein; gynophore 1–1.5 mm; replum straight; style 1–1.5 mm; stigma strongly 2-lobed; ovules and seeds 54–86 per fruit. Seeds broadly oblong, 2–2.7 x 1–1.2 mm; wing continuous, 0.1–0.25 mm wide.
Habitat: glades, steep slopes, sandstone and soft shale in ravines or rocky openings in oak-pine-hickory forests.
Distribution: United States (Arkansas, Oklahoma).