The relationships between Huperzia and related genera of Lycopodiales were studied by chemotaxonomic analysis of alkaloids. Huperzia (18 species, 1 variety and 2 forma) and related genera Phlegmariurus (8 species), Lycopodium (3 species), Lycopodiella (1 species), Palhinhaea (1 species), Diphasiastrum (2 species), and Lycopodiastrum (1 species) were examined by thin layer chromatography for the presence of 10 reference Lycopodium alkaloids, huperzine A, huperzine B, serratine, serratinine, lycodoline, lucidioline, lycopodine, lyconnotine, annotinine, and cernuine. The results indicated that the various genera could be distinguished from one another.