740 SUMMARY OF CURRENT RESEARCHES RELATING TO 



wet and dry patanas, and it is suggested that some factor in the climate 

 of the wet patanas, tending to the evolution of xerophytic characters, 

 may have been overlooked, or its influence undervalued. Such a factor 

 may be presented by the prevalent wind, which by constantly changing 

 the air prevents its approaching but rarely a state of saturation. Again, 

 sufficient importance may not have been ascribed to the lowering of the 

 functional activity of the roots of the wet patana plants by the humic 

 acid in the soil. 



Bdrkill, I. H— On the Variation of the Flower of Ranuncnlns arvensis. 



Journ Asiat. Soc. Bengal, lxxi. (1902) pp. 93-120 (with diagram and 2!) tables) 

 Parsons, H. F r a n k l i n— On the Flora of Hayes Common. 



[Including list of plants.] Proc. and Trans. Croydon Nat. Hist, and 



Sri. Soc, 1902-;; (1903) pp. 52-60. 



CRYPTOGAMS. 



Pteridophyta. 



Cytology of Apogamy.* — J. B. Farmer, J. E. S. Moore, and L. Digby 

 describe certain phenomena in apogamous prothallia of Nephrodium, 

 which afford an explanation of apogamy. In young prothallia, before 

 the appearance of any apogamous outgrowths, cells not infrequently 

 occur in which two nuclei are present. This is found to be due to the 

 passage of a nucleus from a neighbouring cell ; the migrating nucleus 

 may fuse with the original nucleus, or the two nuclei may remain more 

 or less separated for an appreciable time. This migration goes on dis- 

 continuously in a growing apogamous prothallium, producing a cellular 

 aggregate that may possess no very homogeneous character, nor can one 

 cell or even isolated cell-groups be defined as the sole parent tissue 

 from whence the apogamous outgrowth may have sprung. This is in 

 harmony with the irregular growth of the new tissue and with the 

 sporadic appearance of sporophytic members on the prothallium. When 

 the nuclei of the cells in the apogamous regions are examined in course 

 of karyokinesis they are seen to possess a much larger number of 

 chromosomes than those of the ordinary tissue-cells of the prothallium ; 

 there appear to be forty and eighty in the respective classes of nuclei. 

 The authors regard the process as one of irregular fertilisation. The 

 doubling of the chromosomes receives an explanation strictly analogous 

 to that afforded by the normal fusion of oosphere and spermatozoid. 

 But instead of one cell only (the oospore) serving as the starting point 

 for the new generation, a number of such units loosely co-operate to 

 produce it. In this connection it is perhaps significant that the young 

 plantlet is commonly borne on, and produced from, a special sporophytic 

 outgrowth, of which the constituent cells may have become homologously 

 differentiated into a sort of pro-embryo. 



East Asiatic Pteridophyta. t — Y. Yabe gives a list of 53 vascular 

 cryptogams collected in Korea by T. Uchiyama. H. Christ % publishes 

 a list of 33 species collected by E. H. Wilson mostly in Hupeh, with 

 descriptions of four novelties. 



* Proc. Roy. Soc, lxxi. (1903) pp. 433-7 (4 figs, in text). 



t Tokyo Bot. Mag., xvii. (1903) pp. 63-9. 



J Bull. Herb. Boiss., ser. 2, iii. (1903) pp. 508-14. 



