Seven new Lycopodium alkaloids, squarrosusines A-E (1-3, 5 and 6), 8-epilycoposerramine U (4) and squarrosusine F N-exide (7), and 4 related known compounds (8-11) were isolated from the aerial parts of Phlegmariurus squarrosus. The structures of these seven new compounds share a unique heterocyclic C16N-type skeleton. The chemical structures of the new compounds were established through spectroscopic methods, including 2D NMR techniques and mass spectrometry, as well as chemical reaction. The inhibition effects of the isolates against acetylcholinesterase (AChE) were evaluated in vitro. © 2015 Elsevier Ltd. All rights reserved.