In studying the alkaloid compositions of Thalictrum minus and Th. foetidum L. (representatives of the Northern Caucasus flora), we analyzed their epigeal parts and chromosome numbers. Total alkaloids were extracted with chloroform, and individual bases were isolated via column and preparative thin-layer chromatography. Chromosomes were counted from young rootlets and buds fixed with Carnoy's fluid. Results: Th. minus (2n=42) had 0.66% total alkaloids in budding herbage, yielding six bases including thalicberine, O-methylthalicberine, α-allocryptopine, palmatine, base I (N-methylcanadine hydroxide), and base II (new for the genus). Th. foetidum (2n=14) had 0.31% total alkaloids in herbage, yielding three bases including thalflavine (new for the species), magnoflorine, and berberine. Additionally, from Colchicum speciosum corms, we isolated speciosamine (new base, C28H31O6N) from weakly basic fractions via alumina column chromatography. Speciosamine, a tropolone alkaloid, is an analogue of speciosine without a hydroxy group, confirmed by spectral and elemental analysis.