ZOOLOGY AND BOTANY, M1CKOSCOPY, ETC. 47 



Embryo-sac of Habenaria.* — W. IT. Brown has investigated the 

 embryology of Habenaria ciliaris, and finds that a single hypodermal 

 cell develops without division into a megaspore mother-cell. The latter 

 gives rise to two daughter-cells, both of which form two megaspores. 

 There is a probability that in some cases more than one megaspore 

 takes part in the formation of the embryo-sac. The latter contains an 

 egg, two synergidae, two polar nuclei, and three transitory antipodal 

 nuclei. The primary endosperm nucleus results from the fusion of the 

 polar and second male nuclei, but quickly degenerates. There is no 

 evidence in favour of the view that the endosperm is the result of a 

 sexual process. Subsequent to fertilisation a long suspensor and a 

 spherical embryo are formed. 



Embryology of the NympheaceEe.f — M. T.Cook contributes a note 

 upon the development of the Nynipheaceae. The author finds that 

 extra embryo-sacs are frequently formed ; the two nuclei resulting from 

 the first division of the endosperm nucleus are separated by an extremely 

 delicate membrane ; the endosperm is formed from the nucleus at the 

 micropylar end of the sac ; the nucellar tube is subject to great variation ; 

 a suspensor may or may not be formed, and varies much in character. 



Physiology. 

 Irritability. 



Stimulation of Storage Tissue by Zinc Sulphate.^ — B. Silberberg 

 has investigated the effects produced upon storage tissues by solutions of 



zinc sulphate. The strength of the solution varied from— to — , and 



1 A (j 



the plants used were Brassica oleracea, Solanum tuberosum and Trago- 

 ■pogon porrifolius, the best results being obtained with Solanum. The 



results of the experiments show that solutions of strength and 

 produce the best results in stimulating the formation of periderm and 



callus in the meristematic tissues, while solutions of strength — to — 



° 8 1 



retard the development. It is also found that solutions of strength 



and stronger solutions inhibit the respiration of storage tissues, while a 



N 

 solution of — stimulates the respiration. 



General. 



Vitality of Pine Seeds. § — W. C. Coker contributes a short paper 

 upon the delayed opening of pine-cones and the vitality of the seeds 

 contained therein. The author draws attention to Pinus attenuata, 



* Bot. Gaz., xlviii. (1909) pp. 241-50 (12 figs.). 



t Tom. cit., pp. 56-60 (1 pi.). 



+ Bull. Torrey Bot. Club, xxxiii. (1909) pp. 489-500 (4 figs.). 



§ Amer. Nat., xliii. (1909) pp. 077-81. 



