Arabis georgiana Harper
Family: Brassicaceae
Georgia rockcress
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Biennials; sparsely to moderately hirsute (at least basally), trichomes simple, mixed with fewer, short-stalked, forked ones, subsessile cruciform or 3-rayed stellate trichomes commonly on abaxial blade surfaces, sometimes plants glabrous distally. Stems simple or few from base (rosette), erect, unbranched or branched (few) distally, 3-7 dm, (hirsute basally, glabrous distally). Basal leaves: petiole 0.5-2 cm, (ciliate or not); blade spatulate, oblanceolate, or obovate, 1.5-6 cm × 5-15 mm, margins dentate, apex obtuse or acute, abaxial surface moderately to sparsely pubescent, trichomes subsessile stellate, adaxial surface subglabrate or sparsely stellate. Cauline leaves 7-26; blade oblong, lanceolate, or linear-lanceolate, 1.5-7 cm × 3-18 mm, base auriculate to subamplexicaul, margins dentate or entire, apex acute or obtuse, pubescent as basal leaves except distalmost leaves often glabrous. Racemes often simple. Fruiting pedicels erect to erect-ascending, 7-16 mm, (glabrous). Flowers: sepals oblong, 2.5-4.5 × 1-1.5 mm, lateral pair subsaccate basally; petals white, narrowly spatulate or oblanceolate, 6-9 × 1-1.5 mm, apex obtuse; filaments 3-4.5 mm; anthers oblong, 0.8-1 mm. Fruits erect to erect-ascending, (often subappressed to rachis), smooth, 4-7 cm × 0.7-0.8 mm; valves each with midvein extending full length or to middle; ovules 38-44 per ovary; style 0.7-1.8 mm. Seeds narrowly winged throughout, oblong, 0.9-1.9 × 0.5-0.7 mm; wing to 0.1 mm wide distally. Flowering Mar-Apr. Stream banks, roadsides; of conservation concern; 0-200 m; Ala., Ga. Arabis georgiana is most closely related to A. pycnocarpa, from which it is easily distinguished by having narrower fruits, longer petals, and subsessile cruciform or 3-rayed trichomes on abaxial surfaces of basal leaves. It is known only in Alabama from Bibb and Elmore counties and in Georgia from Stewart County.