. The Botanical magazine. Plants; Plants -- Japan. Oct., 1921.] TAKAMHfE?—LIFE HISTORY OF ISOETES. 185 the sporophylls and put in fresh water, the microspores and macro- spores being kept in separate dishes. The fresh water being renewed from time to time, they are to be kft until the spermatozoa are mature and ready for discharge, and the macrospores show their three ribbed opening at the tetra- hedral edge of silicified outer layer of the membrane, rhe fertilization takes place in nature in May in Tokyo. The spores collected in November and kept in culture in a green house or in a thermostat
. The Botanical magazine. Plants; Plants -- Japan. Oct., 1921.] TAKAMHfE?—LIFE HISTORY OF ISOETES. 185 the sporophylls and put in fresh water, the microspores and macro- spores being kept in separate dishes. The fresh water being renewed from time to time, they are to be kft until the spermatozoa are mature and ready for discharge, and the macrospores show their three ribbed opening at the tetra- hedral edge of silicified outer layer of the membrane, rhe fertilization takes place in nature in May in Tokyo. The spores collected in November and kept in culture in a green house or in a thermostat, ripe early in winter (11). The maturity of the spermatozoa may be conveniently tested under the microscope by the use of alowpower objective, e. g. Zeiss B. by the addition of a drop of water saturated with common coal gas, when all the mature spermatozoa are dis- charged in a few seconds ? ethylether, carbonmonoxide as well as ethylene, acetylene, and other unsaturated hydrocarbons may be used for the same purpose itia gaseous form or as an aqueous solution as has been first made known to us by Fujii (8). Gametophyte, Fertilization and Erabryoformation The spermatozoa live very short time after they are once discharg- ed, usually only five to ten minutes swimming in water ? but while they are in antheridia they live pretty long duration, some of them beinp- alive more than one year. In a female gametophyte five or six arcliegonia are developed in general, though sometimes more than ten arcliegonia in a gameto- phyte are met with. At the stage, when the arche- gonium is ready for fertilization, the plasma of the neck canal cell and of the ventral canal cell stains deeply with haematoxylin, and can be distinguished clearly from other cells, and the contents of these cells degenerate, as is common in Lycopodiales. Sometimes there are two nuclei in the neck canal cell (Text- fig. 1),as a result of division of one nucleus without being fol- T? Archegoniumof/.japomca, j^
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectplants, bookyear1887
