735 SUMMARY OF CURRENT RESEARCHES RELATING TO 



outgrowths, and other types exhibit more or less perfect adaptations. 

 The highest developed types are those with the special papillae, 0. cattosum 

 being the most perfect. 



Parthenogenesis in Pinus Pinaster.* — W. T. Saxton contributes 

 a short paper dealing with evidence which tends to prove the occur- 

 rence of parthenogenesis in this species of Pinus. The chief points 

 are as follows. The oosphere nucleus divides before being reached by 

 the pollen-tube or sperm-nuclei. The segregation of the chromosomes 

 into two groups in the first and second divisions of the normal oospore- 

 nucleus cannot be seen. The disorganisation of the apex of the arche- 

 gonium and the displacement of the receptive vacuole which occurs in 

 fertilisation does not take place. The remains of the second sperm- 

 nucleus, tube-nucleus, and stalk-cell, can be distinguished in the upper 

 part of the archegonium in fertilisation, but cannot be seen here. Both 

 parthenogenetic and normal embryos develop, but it is as yet impossible 

 to say whether seeds containing parthenogenetic einbryos are capable of 

 germination. 



Embryo-sac of Passiflora adenophylla.f — M. T. Cook has studied 

 the embryo-sac of Passiflorn adenophylla, and contributes a note upon 

 certain peculiarities which it exhibits. The pollen-tube is very pro- 

 minent, and double fertilisation is a frequent and conspicuous pheno- 

 menon. The most curious feature, however, is the behaviour of the 

 pollen-tube, which often develops abnormally at the expense of the 

 embryo-sac, which it ultimately fills. When this is the case it does not 

 discharge its contents, and no embryo-formation takes place. 



Chemical Solutions and Bud Development.^ — J. W. Harshberger 

 has studied the sequence of bud development, with the object of deter- 

 mining whether it is due to heredity, to the character or disposition of 

 the reserve food, or solely to climatic conditions. The experiments have 

 extended over two years, and the species studied were Quercus palustris, 

 JEsculus Hippocastanum, and several others equally well known. Twigs 

 were grown in various chemical solutions, and although they responded 

 to the stimulus of the chemicals, the sequence of bud-opening was not 

 disturbed. Microscopic studies of the plant-tissues show that the cha- 

 racter and position of the food-material render the protoplasm more or 

 less responsive to external conditions. If the amount of food-reserve is 

 great and easily accessible, the response is rapid, and vice versa, but this 

 relationship must not be pushed too far. Heat appears to be the great 

 factor which determines the opening of buds. 



Physiology. 

 Nutrition and Growth. 



Utilisation of Atmospheric Nitrogen by Specialised Hairs.§ — 

 F. Kovessi contributes a note upon the opinions recently published by 



* Bot. Gaz., xlvii. (1909) pp. 406-9 (7 figs.), 

 t Bun. Torrey Bot. Club, xxxvi. (1909) pp. 273-4 (1 pi.). 

 t Proc. Acad. Nat. Sci. Philadelphia, lxi. (1909) pp. 57-110. 

 § Comptes Rendus, cxlix. (1909) pp. 56-8. 



