From the dried whole plants of Lemmaphyllum microphyllum var. microphyllum and L. microphyllum var. obovatum (Polypodiaceae), α-onoceradiene (I), serratene (II) and onoceranoxide (III) were isolated, and their structures were established by spectroscopic and chemical methods. Colysanoxide (IV), an onoceroid having a novel carbon skelton, was isolated from the dried leaves of Colysis elliptica and C. pothifolia (together with I), and its structure was established by spectroscopic and chemical methods as well as by a X-ray diffraction method. IV was also proved to be found in C. wrightii, C. x shintenensis and C. x simplicifrons by GC-MS. The compounds I-IV could be very characteristic triterpenoids, because they belong to the onoceroid gruop, squalenoids formed by both end cyclization, having no hydroxyl group. They were obtained only from very limited Polypodiaceous ferns.
