摘 要 ：用土壤培养桫椤Alsophila spinulosa (Wall. ex Hook.) R. M. Tryon、中华桫椤A.costularis Baker和白桫椤Sphaeropteris brunoniana (Hook.) R. M. Tryon的孢子，利用光学显微镜对其配子体发育的各个阶段进行了观察，包括孢子形态及其萌发、原丝体发育特点、片状体和生长点的形成及分化、假根特征、精子器和颈卵器的分化及发育，以及原叶体感染真菌后的显微特征。初步讨论了桫椤科不同属（种）间的配子体发育的系统学意义和有性世代的濒危原因。
Abstract:The spores of Alsophila spinulosa (Wall. ex Hook.) R. M. Tryon, A. costularis Baker and Sphaeropteris brunoniana (Hook.)R. M. Tryon were cultivated in soil medium. The gametophyte development of the three species were observed under light microscope in spore germination, filament development, the formation and differentiation of prothallial plate and apical point, the rhizoid feature, and the development and differentiation of the antheridium and archegonium. We also reported ultrastructure of prothallus infected by fungi. The systematic significance of their gametophyte development in Cyatheaceae is discussed, as well as the causes of sexual generation endangerment.