Abstract:In recent years, a new trend of reproductive disorder characterized by seedling reduction was appeared in Chinese Cyatheaceae plants, this test has observed the key link of the behavior and morphology of Cyatheaceae Sphaeropteris lepifera swimming sperm for the first time, in order to explicit the developmental stages of reproductive barrier and anatomic characteristics of Chinese Cyatheaceae plant. (1) Swimming sperm of S. lepifera can be divided into three periods: initial period, stable phase and decline period. After 1-3 seconds of initial period, sperm can accelerate to 200 r·min-1 of the rotation frequency and 130 μm·s-1 of the displacement speed; in 17-22 mins stable phase, sperm rotation frequency and displacement speed are basically stable, sensitive to water quality, namely, the chemical released from archegonium; in 5-7 min of stationary period, sperm rotation frequency, displacement speed and sensitivity to chemical inducer decreased, eventually disappeared. (2) Swimming sperm of S. lepifera is long spiral shape, long 10-12 μm, spiral 2.5-3.5 circles, from top to bottom, it consists of 5 parts: apical ridge, flagellar band, flagella, spermnucleus and vesicle. (3) The flagellar band of S. lepifera is present in the first 1/3 parts of the spermnucleus, there are 32-48 flagella. The cytoplasm was vesicular and atrophy with the time of sperm swimming, spermnucleus was not homogeneous. This paper provides a reference for the study of sexual reproduction Cyatheaceae plants in China.