553 



TJiE (JAMETUPHYTE OF PSILUTUM: PKEJ.IMINAUY 



NOTES. 



Bv Thumas ^A'ihti<:leg(;e, Mkdalist ok thk Koval .SuriETv 

 OF Np^w South Wales, 1899. 



(Vonnniinirafcd hji tJv^ Rrr. 11'. IT. Walls.) 

 (Plate xlv.) 



These Notes are an atteini)t to elucidate tlie luysterx' ot the 

 sexual reproduction of FsUotiivi, which has hitherto ehided all 

 the researches of investigatoi's. 



As far back as 1899, at the request of Dr. J. P. Hill, late of 

 Svdnev, now Professor oi Zoology in University College, London, 

 I sowed spores of Fsilolinii Iriijiii'trniu, and these spores were 

 subjected, by Dr. Hill and myself, to continuous observation for 

 some time. The spores germinated, but as we failed to get any 

 light upon the method of germination, the observatit)ns were 

 discontinued. The spores, in this case, were sown on the dead, 

 barren fronds of Platycerium alcicorne, and the aim of the ex- 

 periment was to discover a visible prothallus. This search for a 

 prothallus was evidently the reason of our failure, as it has pro- 

 bably been the reason of the failure of other investigators. 



After a lapse of 15 years, I decided, in 1915, to try growing 

 the spores upon a living plant, and, for this purpose, selected 

 the aei'ial I'hizomes of Davallia pyxidata Cav., seeing that the 

 two plants were of ten found gi'owing in proximity to one another. 



.Spores Were sown thickly, on prepared rhizomes, on November 

 L'Oth, 1915; and the method adopted was as follows. A 5" pot 

 was filled with soil to within an inch of the brim, the soil having 

 Ijeeii sterilised by dry heat, and by soaking it in several changes 

 of boiling water. When cool, the surface was covered with pieces 

 of the rhizomes of D. pyxidatd. While the surface was fairly 

 wet, Psilotum-spores were dusted o\ er it, after which a sheet of 



