Physiology of AnUieridixim Formation in Ferns 721 



Preliminary investigations actually indicate that Polypodium aiireum 

 (personal communication from M. Ward, 1959) and Onoclea seii- 

 sibilis (author's result) are self-fertile. 



ACKNOWLEDGMENT 



The author wishes to express his gratitude to Dr. Armin C. Braun 

 for his encouragement of these investigations and for the stimulating 

 discussions on the subject of this report. He is also indebted to Drs. 

 Armin C. Braun, Francis O. Holmes, and Tom T. Stonier for criti- 

 cally reading the manuscript and to Dr. C. V. Morton for his help 

 with the identification of the plants. 



LITERATURE CITED 



1. Albaum, H. G. Inhibitions due to growth hormones in fern prothallia and 

 sporophytes. Amer. Jour. Bot. 25: 124-133. 1938. 



2. Campbell, D. H. The Structure and Development of Mosses and Ferns. 3rd ed. 

 708 pp. Macmillan Co., New York. 1918. 



3. Czaja, A. T. Zur Frage der habituellen Diozie bei Onoclea struthiopteris Hoffm. 

 Ber. Deutsch. Bot. Ges. 42: 300-304. 1924. 



4. Dopp, W. Gestaltung und Organbildung innerhalb der Gametophytgeneration 

 der Polypodiaceen unter besonderer Beriicksichtigung genetischer Gesicht- 

 spunkte. Beitr. Biol. Pfl. 24: 201-238. 1936. 



5. . Fine die Antheridienbildung bei Farnen fordernde Substanz in den 



Prothallien von Pteridium aquilinum (L.) Kuhn. Ber. Deutsch. Bot. Ges. 63: 



139-147. 1950. 

 6. . Uber eine hemmende und eine fordernde Substanz bei der Antiieridien- 



bildung in den Prothallien von Pteridium aquilinum. Ber. Deutsch. Bot. Ges. 



72: 11-24. 1959. 



7. Fames, A. J. Morphology of Vascular Plants. Lower Groups. (Psilophytales to 

 Filiales). 433 pp. McGraw-Hill Book Co., Inc., New York. 1936. 



8. Mottier, D. M. Notes on the sex of the gametophyte of Onoclea struthiopteris. 

 Bot. Gaz. 50: 209-213. 1910. 



9. Naf, U. The demonstration of a factor concerned with the initiation of 

 antheridia in polypodiaceous ferns. Growth. 20: 91-105. 1956. 



10. On the physiology of antheridium formation in the bracken fern 



[Pteridium aquilinum (L.) Kuhn]. Physiol. Plant. 11: 728-746. 1958. 



11. . Control of antheridium fonnation in the fern species Anemia phy ni- 

 tidis. Nature. 184: 798-800. 1959. 



12. . On the control of antheridium formation in the fern species Lygodium 



japouicum. Proc. Soc. Fxper. Biol. Med. (In preparation.) 



13. Prantl, K. Beobachtungen uber die Frniihrung der Farnprothallien und die 

 Vertheilung der Sexualorgane. Bot. Zeit. 39: 753-758, 770-776. 1881. 



14. Raper, J. R. Sexual hormones in Achlya. VII. The hormonal mechanism in 

 homothallic species. Bot. Gaz. 112: 1-24. 1950. 



15. Wilkie, D. Incompatibility in Pteridium aquilinum (bracken). Abstr. Hered. 

 7: 1504. 1953. 



16. Wuist, F. D. The physiological conditions for the development of monoecious 

 prothallia in Onoclea struthiopteris. Bot. Gaz. 49: 216-219. 1910. 



