Abstract: The developments of male and female gametophyte and juvenile sporophyte of Selaginella tamariscina (Beauv.) Spr.were studied. They have been grown in culture. The microspores and the macrospores of Seiaginella are all tetrahedral type and trilete. In the present species, the microspores are reddish orange and the macrospores are yello-wish. The microspores are cultured when they shed from their microsporangia. They deyelop into male gametophytes in a week, and the majority of them produce spermatozoids in 20 days. The male gametophyte consists essentially of a single antheridium. When the spermatozoids are extruded from the antheridium, it is enveloped by a membrane, its body is curved like a bow 5μm. in diameter. After 2-3 minutes they stretch their biflagella and begin to swim. The length of the extended spermatozoid is about 9-10 μm. Its flagella is about 25-28 μm. The macrospores are treated in low temperature about 5℃. in refrigerator for 6-8 weeks and then cultured. They develop into white female gametophytes and emerge from the split in the trilete of the walls of macrospores in 5 weeks.The exposure of the female gametophyte is followed by the appearance of the archegonia in them. The number of the archegonium in a female gametophyte is about 15 even to 40.Because of their brown in color when they ripen, they can be recognized easily. An archegonium only projects with its four opercular cells above the level of the female gametophyte.These cells are triangular shield-shaped. At the trilete end of the macrospore the female gametophyte produces cells on its surface, and at the other end there is non-cellular structure storing its nutrition. The microspores and the macrospores are collected and mixedly cultured. Their juvenile sporophytes appear in 5 days.Its percentage is very low about 2.1-3.3%. At first the hypo-cotyledonary stem of them grows up and then it produces the hyprimary root. The two cotyledons which are on the top of the pocotyledonary stem expand. Accompanying growth the apical cells of stem extend and produce leaves, axillary buds and adventitious root. It is interesting to note that the tip of the primary root may branch dichotomously. In the present work, the percentage of the germination of the macrospores treated in low temperature greatly increases.This leads the author to consider that the macrospores in nature need a ripened period through a winter and germinateand develop into female gametophytes next spring. The micro-spores and the macrospores which do not be treated in low temperature are mixedly cultured, the percentage of the appearance of the sporophyte is very low. It is possible that the severy few macrospores which develop into female gametophytes and are fertilized may be shed last year. They seem to be sliped into the culture.