I 



ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 171 



nigra and /. regia. A brief summary is given by C. J. Chamberlain.* 

 Among the seed-plants there is an evident tendency to reduce the male 

 gamete so that the male cytoplasm does not take part in fertilization. 

 In this reduction the binucleate generative cell has played an important 

 part. Its appearance in the Gymnosperms (Abietineae, some Taxacese, 

 Gnetales) is accompanied by a constantly increasing disorganization of 

 the male cytoplasm, which finally leads to the naked sperm-nuclei of 

 the higher Angiosperms. The species of Juglans studied have l)inu- 

 cleate o'enerative cells which reach the embrvo-sac without disori>'aniza- 



O I/O 



tion, and correspond exactly to the binucleate generative cells of certain 

 Gymnosperms. In this feature, therefore, these species occupy an 

 intermediate position between Gymnosperms, in which the cytoplasm 

 reaches the egg-cell, and the higher Augiosperms, in which the male 

 cytoplasm disorganizes in the pollen -tube or even in the pollen-grain. 



The persistence of the male cytoplasm in Juglans is thought to be 

 a primitive character retained from their Gymnosperm ancestors, and 

 the appearance of this character in chalazogams is said to be significant 

 and is a further proof of the great age of these plants. The tendency 

 in seed-plants to reduce the male gametes seems correlated with the ap- 

 pearance of the pollen-tube, for the simpUfication of the male gametes 

 goes hand-in-hand with the evolution of the pollen-tube. 



Structure and Development. 

 Veg-etative. 



Ray Tracheids in the Coniferales.t — Ruth Holden has investi- 

 gated the presence or absence of ray tracheids in extinct and living 

 Conifers. These elements are found to be normally present in Pity- 

 oxyla onwards from the Middle Cretaceous period, and also in the 

 Abietine83. In the Taxodine^ and the Cupressine^ they are developed 

 as the result of injury to the branch ; and, on the evidence of the 

 traumatic recapitulation of ancestral characters, the author concludes 

 that the Taxodinege and Cupressinese are descended from Abietinese, 

 having sprung from that line at some time after the Middle Cretaceous 

 period. Ray tracheids are universally absent in the Podocarpinese, 

 Taxine^e, and Araucarinese, hence their lines, it is suggested, must 

 have come off from the Abietinete at some time before the Middle 

 Cretaceous. These conclusions are corroborated by a study of geo- 

 logical records and of other anatomical structures, such as resin-canals, 

 wood parenchyma, etc. 



Anatomy of Stomata of Dicotyledons. I — B. Hryniewiecki con- 

 tributes a further paper upon the stomata of Dicotyledons. The new 

 type recently described by the author, as characteristic of the Saxi- 

 fragacete, has now been found in the Cunoniace^e, Platanaceae, Rosaceas, 

 Celastraceae, and Composit^e. In several of the Senecione^e three types 

 are common, viz., the normal type, the newly-described " trichter " 



* Bot. Gaz., Iv. (1913) pp. 94-5. 

 + Bot. Gaz., Iv. (1913) pp. 54-64 (2 pis.). 



X Bull. Internat. Acad. Sci. Cracovie, Ser. B, 1912 (Cracow), pp. 585-605 (5 pis.). 



N 2 



