ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 491 



BOTANY. 



GE NEBAL, 

 Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 "Vegetative and Reproductive. 



Pollen-formation.* — M. Ghiignard contributes a note dealing with 

 methods of pollen-formation and their significance. It is shown that 

 there are many exceptions to the general rule that successive Id- 

 partition is characteristic of Monocotyledons and simultaneous quadri- 

 partition of Dicotyledons. In addition to the exceptions found in 

 Asphodel us, Hemerocallis, and in several species of CeratophyUum, 

 Raflesia, Asclepias, and Apocynum, the author states that in all the 

 Orchidaceas which he has examined Cypripedium is the only one which 

 exhibits successive bipartition. Many members of one tribe of the 

 Liliacere, i.e. the Aloineae, form their pollen in the same way as Dicoty- 

 ledons ; the same method is found in several species of Iris, Sisyrin- 

 ehium, Txia, etc. Recently Samuelsson has shown that in Aristolochia 

 Clematitis and Anona cherimola the pollen-development is abnormal. 

 In the former species wall-formation is successive and normal, but the 

 thickening of the first wall is unusually rapid. In the second species 

 there is a tendency to wall-formation immediately after the first division 

 of the nucleus ; subsequent division is normal. The last case agrees 

 with Magnolia and Liriodendron, which may be regarded as intermediate 

 between the Monocotyledons and Dicotyledons ; the formation of the 

 incomplete wall favours a nearer relation with the Monocotyledons. The 

 author agrees with Samuelsson in the opinion that the occurrence of 

 the same type of pollen-formation in the Magnoliacege and Anonacea?, 

 on the one hand, and in the Aristolochias and Monocotyledons, on the 

 other, offers important phylogenetic considerations. 



CRYPTOGAMS. 



Pteridophyta. 

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



Branching and Branch-shedding of Bothrodendron.f — Marjorie 

 Lindsey publishes some new evidence about the ulodendroid scars of 

 Bothrodendron. Two new specimens of B. minutifolium are described, 

 one showing ramification of a type hitherto undescribed. It consists 

 •of the end of a main axis, with opposite rows of alternate branches 

 with trumpet-shaped bases. The cortex of the main stem is continuous 



* Comptes Rendus, clx. (1915) pp. 428-33. 



t Ann. Bot., xxix. (1915) pp. 223-30 (1 pi. and 3 figs.). 



