Thalictrum coriaceum

Roots bright yellow, tuberous. Stems erect, coarse, 65-150 cm, glabrous. Leaves cauline; petioles of proximal leaves well developed, clasping stem, distal leaves sessile or nearly so. Leaf blade 1-4×-ternately compound; leaflets reniform or obovate to orbiculate, apically 3-9-lobed or toothed, 10-75 mm wide, lobe margins crenate, surfaces abaxially glabrous or glandular. Inflorescences panicles, pyramidal, loosely branched, many flowered. Flowers: sepals white to purplish, lanceolate-ovate, 1.5-5.5 mm; filaments maroon, 4-4.5 mm; anthers 2-5.5 mm, apiculate, subulate-tipped; stigma maroon. Achenes 3-15, erect, not reflexed, stipitate; stipe ± wing-angled, 0.7-2.5 mm; body obliquely ovoid to ellipsoid, not laterally compressed, 3-6.5 mm, strongly veined or ribbed, veins not anastomosing; beak 1.5-3 mm.

Flowering mid spring-late spring (late May-Jun). Rocky or mesic, open, deciduous woods, thickets, and moist alluvium, chiefly in mountains and piedmont; 3-1100 m; D.C., Ky., Md., N.C., Pa., Tenn., Va., W.Va.

Glandular plants of Thalictrum coriaceum have often been misidentified as T . revolutum despite important differences in the leaflets, the latter having entire rather than crenate lobe margins.

Studies by M. Park and L. Morse (unpubl.) for The Nature Conservancy confirmed that Thalictrum steeleanum is highly variable in all allegedly diagnostic characters and is not distinct from T . coriaceum .

Stems to 1 m, from a stout caudex; upper lvs sessile, the terminal lfl in each set of 3 commonly triangular-obovate, longer than wide, narrowed to the base; panicle very loosely and widely branched; filaments slender, colored; anthers 2.5-3.5 mm; achenes short-stipitate, turgid, ovoid, 2.5-4 mm long and half as wide, the upper side more convex than the lower; style persistent, usually deflexed; 2n=70, 140. Rich woods in and near the mts.; Md., Va., W.Va., Ky., Tenn., N.C., and Ga. Late May, June.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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