FERN GROWING 



123 



EXPERIMENT NO. XLVII. 



Fig. 56. — The manner in which a prothallus was divided. 



Dividing the Prothalli. 



Spores were sown thinly in the autumn of 1887,* so as to 

 produce vigorous prothalli that would allow a division into 

 two, three, or four parts. In 1888 a number of these were 

 cut with a sharp knife, some into two, and others into four 

 parts ; the experiment was successful, as nearly every division 

 grew, for if divided where there were no rootlets some soon 

 formed when under bell-glasses. Twenty-five prothalli were 

 quartered, and nearly a hundred plants were obtained, but 

 although they grew into sturdy little tufts (much more 

 bush-like than the prothalli that had not been divided), still 

 they bore no fronds, nor did they until these quarters were 

 planted in pairs so as to overlap each other, and then a large 

 proportion formed fronds ; those that did not throw up fronds 

 had other divisions planted against them, and by 1892 they 

 could all be potted off as young plants, and a portion had even 

 become mature plants. 



* In the experiments made in quartering prothalli in 1887, those recorded as 

 Nos. 16, 20, 29, 31, 312, 316 to 320, 323, 328, 331, 332, 340, and 343 were unmistak- 

 ably conclusive ; and where two plants were seen that apparently sprang from the 

 same prothallus (before being divided), in Nos. 10, 12, 54, 90, 92, and 330 (when 

 they had attained maturity), -the plants from the same prothallus in all these six 

 cases were exactly aUke/ These being repetitions are not further mentioned. 



