Isoln from Lycopodium annotinum L., Lycopodiaceae: Manske, Marion, Can. J. Res. 21B, 92 (1943). Structure: Przybylska, Marion, Can. J. Chem. 35, 1075 (1957); Wiesner et al., Tetrahedron 4, 87 (1958); Przybylska, Ahmed, Acta Crystallogr. 11, 718 (1958). Stereochemistry: Wiesner et al., Tetrahedron Lett. 1961, 187; Ho, ibid. 1969, 1307. Synthesis: Wiesner et al., Can. J. Chem. 47, 433 (1969). Biogenesis: Leete, Tetrahedron 3, 313 (1958).