312 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Reproductive. 



Fertilization in Fritillaria pudica.*— K. Sax finds tbis species 

 exceptionally good for the study of the process of fertilization. Strong 

 chromacetic acid and Flemming's stronger solution were used as fixatives. 

 Most of the sections were cut 10 /x thick, but a few 15 /a and 20 fi ; they 

 were stained with modifications of Flemming's triple stain and with 

 safranin and lichtgriin. The results obtained may be summarized as 

 follows :■ — In the mature embryo-sac of Fritillaria pudica the egg-cell 

 cannot be distinguished from the other two cells of the egg-apparatus. 

 The " Endospermanlage " extends up between and around the cells of 

 the egg-apparatus. The pollen-tube usually turns along the outer wall 

 of the nucellus or embryo-sac before entering. At this time the cells of 

 the egg-apparatus are all intact. The pollen-tube practically always 

 enters and at least partly destroys one synergid. Although a distinct 

 appearance of motility is evident in many male nuclei, the majority do 

 not suggest much motility. The male nucleus and the Qgg nucleus "fuse 

 completely before division. The upper polar nucleus, with the male 

 nucleus in contact with it, migrates to the lower one, probably cyto- 

 plasmic streaming. The two polar nuclei and male nucleus fuse 

 completely, and the subsequent division is normal. The two red bodies 

 the " X-Korper " of Nawaschin, which remain in the pollen-tube after 

 the male nuclei have been discharged are probably nuclei, and correspond 

 to the two vegetative nuclei described in the pollen- tube before the two 

 male nuclei were discharged. 



CRYPTOGAMS. 



Pteridophyta. 



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



Acrostichoid Ferns-f— F. 0. Bower, continuing his studies in the 

 phylogeny of the Filicales, publishes his sixth contribution, " Ferns 

 showing the ' Acrostichoid ' condition, with special reference to Dipteroid 

 Derivations." He gives the following summary of the chief results 



* Bull. Torrey Bot. Club., xliii. (1916) pp. 505-22 (3 pis.). 

 t Ann. Bot., xxxi. (1917) pp. 1-39 (2 pis. and figs.). 



