ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 321 



have the same kind of stomata, similar glandular and simple hairs, and 

 the same peculiar crystals of calcium oxalate ; many genera have the 

 same structure in the midrib of the leaf, while the stem has sub- 

 epidermal periderm, sclerotic tissue, etc. The Myricacefe show similar 

 characters in stomata, hairs, crystals and stem- structure. 



Reproductive. 



Embryo-sac of Epipactis.* — W. H.Brown and L. \V. Sharp de- 

 scribe the development of the embryo-sac and embryo in Epipactis 

 pubescens. They find that the archesporium consists of a single hypo- 

 dermal cell, which becomes the megaspore-m other-cell ; the latter in 

 most cases forms two unequal daughter-cells, the chalazal one dividing 

 to form two megaspores, and the innermost megaspore then gives rise 

 to the emltryo-sac. In other cases four megaspores take part in the 

 formation of the sac, the walls appearing at the first two divisions of 

 the megaspore-mother-cell being evanescent. The mature embryo-sac 

 contains an egg, two synergids, three evanescent antipodal cells, and two 

 polar nuclei which fuse. The usual type of double fertilization occurs, 

 and the fertilized egg gives rise to an embryo which has no suspensor. 

 The endosperm nucleus disorganizes without dividing. The authors 

 consider that the variety of methods by which the embryo-sac of Epipactis 

 is formed may be regarded as a series representing a reduction in the 

 number of nuclear divisions occurring between the archesporial cell and 

 the formation of the egg. 



Anomalous Development of the Embryo-sac of Euphorbiaceae.f — 

 J. Modilewski has studied the development of the embryo-sac in several 

 of the Eupliorbiacea3, and finds that in at least two cases there is a 

 marked deviation from the normal course. Usually only one arche- 

 sporial cell is present, daughter-cells are formed when there are four 

 nuclei, and finally there is a typical eight-nuclear embryo-sac. In 

 E. procera and in E. palustris, an archesporium is formed, no daughter- 

 cells are partitioned off when there are four nuclei, and finally the ripe 

 embryo-sac contains sixteen nuclei as a result of the repeated division 

 of the nuclei. E. lucida and E. virgata are slightly anomalous in the 

 number and position of the nuclei, and the author thinks it probable 

 that investigations will reveal further anomalies in other species. 



Physiology. 

 Nutrition and Growth. 



Stomatal Movement in Plants.| — B. E. Livingston and A. H. 

 Estabrook have studied the movements of the stomata in Funkia ovata, 

 Isatis titictoria, AUium Cepa, EichJwrnia speciosa, and CEnothera biennis, 

 and their results show that the diffusive capacity reached zero at night 

 in all cases except Allium, Eichhornia, and the lower leaf-surface of 

 Oenothera. "VYlien the index of diffusive capacity had vanished, a certain 

 amount of transpiration still continued, not only through the cuticle and 



* Bot. Gaz., cii. (1911) pp. 439-52 (1 pi.). 



+ Ber. Bot. Gesell., xxix. (1911) pp. 430-6 (1 pL). 



X Bull. Torrey Bot. Club, xxxix. 1 (1912) pp. 15 22. 



