68 SUMMARY OF CURRENT RESEARCHES RELATING TO 



CRYPTOGAMS. 



Pteridophyta. 

 (By A. Gepp, M.A., F.L.S.) 



Apogamy and Apospory.* — H. "Woronin discusses the question of 

 apogamy and apospory in certain ferns. She has discovered apogamy in 

 Notochlama EcMoniana, N. sinuata, Pellcm tenera, P.flavens, and has 

 followed out the development of the germinating plants in these as well 

 as in Trichomanes Kranssii. And in the latter plant she has also 

 followed out the development of the antheridia and the formation of the 

 prothallium, which usually is a flat expansion arising from a filament. 

 In this plant also she produced apospory artificially. Various physio- 

 logical experiments made by the author are described, and a full 

 summary of her results is given. 



K. Goebel f has succeeded in producing apospory artificially in various 

 ferns, obtaining prothallia, sporophytes, and intermediate structures. He 

 finds that regeneration is more active in young than in older leaves ; 

 that the product of regeneration is not necessarily a sporophytic struc- 

 ture ; that there seems to be no great difference between the nuclei of 

 prothallia and those of sjwrophytes, and so no sharp distinction between 

 the x and 2x generations. 



Genus Antrophyum.J — R. C. Benedict treats of the genus A/itro- 

 phyum, giving a synopsis of its sub-genera and of the American species. 

 Four sub-genera are distinguished, one of them being new, Antrophy- 

 opsis, which comprises five African species, A. Boryanum being the type. 

 Nine American species are recognised and re-described. Two of them 

 are new, A. Dussianum from the West Indian Islands, and A. Jenmani 

 from British and French Guiana. 



Bryophyta. 



(By A. Gepp.) 



Apospory and Sexuality in Mosses.§ — El. and Em. Marchal give 

 an account of the methods and results of their experiments undertaken 

 to determine the sexuality of the protonemas obtained by cultivation of 

 portions of pedicel and theca of the maturing sporogonium, Stahl 

 and others having already shown the possibility of obtaining such a 

 protonema by regeneration. Results were obtained with fourteen 

 species, but only those derived from three dioicous species, Bryum 

 caespiticium, Mnium hornum, and B. argenteum, are now published. 

 1. The aposporic protonema resulting from the regeneration of the 

 sporophyte is morphologically identical with the haploidic protonema ; 

 placed in favourable conditions it is apt to produce gonophytes. 2. 

 These gonophytes are bisexual, like the sporogonium, from which they 

 emanate. 3. This double sexual polarity expresses itself in the 



* Flora, xcviii. (1907) pp. 101-62 (figs.). 



+ SB. k. Akad. Wiss., xxxvii. (1907) pp. 119-38 (figs.). See also Bot. Gazette, 

 xliv. (1907) p. 317. X Bull. Torrey Bot. Club, xxxiv. U907) pp. 445-58. 



§ Bull. CI. Sci. Acad. Koy. Belg., 1907, pp. 765-89. See also pp. 728-30. 



