Thalictrum arkansanum

Roots brown, thick, tuberous. Stems decumbent, 20-40 cm, glabrous. Leaves: distal cauline long-petiolate. Leaf blade 1-3×-ternately compound; leaflets ovate to obovate to reniform or orbiculate, 3-(or more)-lobed, largest leaflets less than 15 mm wide, lobe margins crenate, surfaces glabrous. Inflorescences terminal, racemes, few flowered. Flowers: sepals whitish, ovate or elliptic, 0.9-2.8(-3) mm; filaments colored, 2-3 mm; anthers 1.8-2.3 mm, mucronate, tip 0.1-0.4 mm; stigma color unknown. Achenes few, not reflexed, nearly sessile; stipe 0.1-0.3 mm; body ellipsoid to oblong, 3.5-4.5 × 1.5-2 mm, glabrous, veins 10-12, not anastomosing-reticulate; beak (1.3-)2.3-3 mm.

Flowering early spring (Mar-Apr). Wet bottomland forest, sometimes upland woods; of conservation concern; 20-150 m; Ark., Okla., Tex.

Poorly known, Thalictrum arkansanum is closely related to T . texanum and T . debile ; it possibly should be considered as a variety of the latter.