﻿GERMINATION AND GAMETOPHYTE OF FERNS. 



121 



Summary. 



1. Under ordinary conditions spores of Cyatheaceae and 

 other ferns experimented with, do not germinate in darkness 

 when sowed upon leaf -mold. 



2. Higher temperature than ordinary room temperature 

 was not sufficient to induce germination of Alsophila pruinata 

 and Aneimia phyllitidis in darkness. 



3. Germination was best in light of medium intensity, about 

 0.075 sunUght. 



4. Intensity of hght affects form of prothallia, weaker light 

 producing filamentous or ribbon-like prothallia, while strong 

 light produces heart-shaped prothallia in ail except Aneimia, 

 which has a lateral growing point. 



5. Strong light of intensity of 0.3 causes production of 

 archegonia only in Alsophila pruinata, while in other ferns 

 worked with, archegonia and antheridia were produced. 



6. Weak light inhibits the production of archegonia and 

 favors the production of antheridia. 



7. Young stages of the prothallia of A. pruinata, Aneimi/x 

 phyllitidis, and Gymnogramme are strongly and positively 

 heliotropic. 



In conclusion I wish to express my thanks to Professor 

 Wm. Trelease and Professor S. M. Coulter for valuable sug- 

 gestions in the preparation of this paper. 



BIBLIOGRAPHY. 



1. Arcangeli, G. Sulla PUularia e Salvinia. (Nuovo Giomale Botanico 



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2. Beck, G. Entwicklungsgcschichte des Prothalliums von Scolopend- 



rium \-ulgare. (Rev. in Bot. Zeitung. 36 : 780. 1878). 



3. Bittner, K. Ueber Chlorophyllbildung im Finstem bei Kryptogamen. 



(Oes'terr. Bot. Zeitschr. 65 : 302. No. 8. 1905). 



4. Borodin, J. Ueber die Wirkung des Lichtes auf einige hohere 



Kryptogamen. (Bull, de I'Acad^m. Imp. des Sciences de St. P^- 

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5. Burgerstein, A. Bot. Centralb. 88 : 105. 1901. 



6. Goebel, K. Laboratory note (Flora. 83 : 74-75. 1897). 



