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Thalictrum
See list of 6 species in this genusReference: Park and Festerling (1997).
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1a. Leaves subtending the inflorescence opposite (though sometimes appearing whorled when the leaves are divided to the base); sepals 5–18 mm long, conspicuous, usually persisting through anthesis
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1b. Stem leaves alternate; sepals 1.5–5 mm long, often inconspicuous and sometimes caducous
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2a. Leaflets mostly with 3 lobes, each lobe entire and without additional sublobes; filaments usually white, sometimes tinged with purple, somewhat to prominently dilated distally (slender throughout in T. dasycarpum); anthers 0.5–2.7 (–3) mm long (up to 3.6 (–4) mm long in T. dasycarpum)
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3a. Filaments ± slender throughout; anthers 1–3.6 (–4) mm long, usually with a prominent apiculus at the apex
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3b. Filaments somewhat to prominently dilated distally; anthers 0.5–2.7 (–3) mm long, without an apiculus at the apex or a poorly developed one
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4a. Abaxial surface of leaflets with sessile or stalked glands or white-papillose; achenes usually stipitate-glandular
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4b. Abaxial surface of leaflets lacking glands or papillae; achenes glabrous or pubescent with eglandular hairs
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2b. Leaflets with 4 or more lobes, these often appearing as 3 lobes and each lobe with 1–3 tooth-like sublobes [Fig. 821]; filaments colored, usually red-purple to purple or yellow to green-yellow, ± slender throughout; anthers 2–4.5 mm long
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5a. Lowest branch of the inflorescence subtended by a short-petioled leaf, the petiole shorter than 30 mm; achenes inwardly curved; plants with rhizomes, flowering from early June through early August
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5b. Lowest branch of the inflorescence subtended by a long-petioled leaf, the petiole 30–60 mm long; achenes straight; plants arising from a stout caudex, without rhizomes, flowering from early May through early June
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Each photo represents one species in this genus.