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in most of the larger botanical text-books. Later, the prothalli 

 were formed, but the spermatozoids were not seen in a motile 

 condition at this time owing to the lack of continuous observa- 

 tion. They were seen, however, in great numbers after the 

 motile period, filling the walls and passage-way of the gelatinous 

 funnel which forms about the female prothallus. In May, 1901, 

 the experiment was repeated with similar results. In May, 1902, 

 a sporocarp from the same material, having then been in the 

 herbarium practically eleven years, was placed in water, and the 

 stages of the resulting germination of the spores were watched 

 more carefully. Swarms of motile spermatozoids were noticed after 

 about fourteen hours, and for eight hours longer a greater or 

 less number could be found in motion. Nearly every spore in 

 the sporocarp germinated. Some of the megaspores were finally 

 removed from the water and kept upon wet filter-paper for ten 

 days, when embryo-sporophytes, with the first leaf a centimeter 

 long, had developed. The remarkable vitality of these eleven- 

 year-old spores naturally suggested that the age-limit for ger- 

 mination had not been reached, and attempts were made to ger- 

 minate spores from about twenty other specimens of various species 

 which had lain in the herbarium for periods varying from twelve 

 to thirty years. In one of these cases the attempt was suc- 

 cessful. This was with material of Marsilea vestita preserved in 

 Professor Underwood's herbarium, and collected by Mr. W. N. 

 Suksdorf, in Falcon Valley, Washington, the pocket bearing the 

 double date "Nov., 1883" and "Aug., 1884." The spores 

 were germinated on June 7, 1902, so that even supposing 

 August, 1884, the later of the two dates, to be the correct one 

 for the material used, vitality had been retained for practically 

 eighteen years. Six sporocarps were tried, all of which opened 

 in the normal fashion. Nearly all of the megaspores formed 

 prothalli with archegonia. After fertilization, embryos of con- 

 siderable size were grown by sowing the spores on damp filter- 

 paper. Of the microspores, practically all showed advanced 

 stages of germination, such as the formation of the prothallus 

 and protrusion of the antheridum, but only about a half of them 

 set free motile spermatozoids. The first free spermatozoids were 

 seen in 1 1 ]/± hours after the sporocarps were placed in water. 



