000 SUMMARY OF CURRENT RESEARCHES RELATING TO 



continue to grow, but develop peculiar forms and branching of various 

 types. The sex-organs continue to develop, antheridia being found 

 occasionally on the main plant in all positions, but especially on the 

 branches. Archegonia become very numerous, approximately : J >00 

 having been found on one gametophyte. These not only develop in the 

 apical region, but also far back among the old archegonia. Fertiliza- 

 tion may take place whenever liquid water is present, as shown in 

 several cases where gametophytes were placed in water and sectioned 

 later. Apogamy is present in a sporangium-like structure which lacked 

 the long stalk of the Polypodiaceas, but was not unlike the younger 

 stages of the sporangium of the Osmundacea3. It had t\vo layers of 

 cells outside the fertile region, the inner of these layers resembling a 

 tapetum. 



Culture of Fern Prothallia.* — E. D. Wuist obtained good results 

 by cultivation in porous pots in bright light, the transpiration being 

 carefully regulated. Most of the prothallia were dioecious : but 

 archegoniiferous prothallia were made monoecious by placing them in a 

 nutritive solution for 4 to 7 days. As to spores, they germinated readily 

 in water in bright light (but less readily in nutritive solutions), and, 

 when later transferred to nutritive solutions, they produced normal 

 dioecious prothallia. Young sporophytes produced continued to grow 

 in the nutritive solutions. 



Geography of Ferns.| — H. Christ publishes a detailed book on the 

 geographical distribution of Ferns, dividing the subject into two parts. 

 1. Ferns under the influence of soil and climate. In this part he treats 

 of soils, climatic conditions of all sorts, hygrophytes and xerophytes, with 

 their various modifications, arctic and alpine ferns, etc. 2. Fern floras. 

 In this part he treats of the principles of floristic botany, such as distri- 

 bution in its various aspects : endemism, cosmopolitanism, invasions, 

 survivals, etc ; the main floral regions — north temperate, Mediterranean, 

 Chinese-Japanese, Malayan, Australasian, tropical African, South African 

 and African Islands, Mexican, tropical American, South Brazilian, Andes, 

 South Chile. A bibliography is provided. 



Olaf Swartz's Types of Ferns.t — C. Christensen gives an account 

 of some ferns of Olaf Swartz's herbarium, now intercalated in the general 

 herbarium of the Riksmuseurn in Stockholm. He enumerates twenty- 

 three of Swartz's types, adding critical comments. In a second list he 

 gives seven Swartzian species which are included in the ordinary hand- 

 books ; the types of these are shown in photographs. In a third list 

 he gives eight of Cavanilles's species, which were described in 1802-3, 

 and which it is possible to recognize, thanks to authentic fragments 

 found in Swartz's herbarium. 



Relationships of the Genera of the VittarieaB.§ — R. C. Benedict 

 discusses the relationships of the genera of the Vittariere. This tribe of 

 ferns seems to furnish a good illustration of the law of recapitulation, 



* Mich. Acad. Sci., 11th Rep. (1909) p. 37. 



+ Die Geographie der Fame. Jena : Fischer (1910) 358 pp. (129 figs, and 3 maps), 



X Arkiv Bot., ix. No. 11 (1910) 46 pp. (5 pis. and figs.). 



§ Journ. New York Bot. Gard., xi. (1910) pp. 101-2. 



