ZOOLOGY AND BOTANY, MICROSCOPY, ETC. j6<9 : I 



the basal segment. The organs of the embryo originate in the distichous 

 manner characteristic of the vegetative leaves of grasses. 



Embryology of Quercus.* — Mr. Abram H. Conrad gives a few 

 details of the development of the embryo in Quercus (yelutina and 

 coccinea tinctoria). During the first year the carpels fuse so as to form 

 three nearly distinct loculi ; but it is not till the following spring that 

 the first indication of an ovule is manifest. The mature embryo-sac 

 contains the usual two groups of four nuclei each. There occurs an 

 early fusion of the polar nuclei, followed by a copious development of 

 endosperm. The first division of the ovum-cell is transverse, and the 

 suspensor undergoes but one subsequent division, which is vertical. 



Fertilisation of Cynomorium-t — Sig. E. Pirotta and Dr. B. Longo 

 state that, in Cynomorium coccineum the ovule is destitute of a micro- 

 pyle, the pollen-tube finding its way to the embryo-sac through a vacuo- 

 lated and amyligerous cone of tissue in the micropylar region of the 

 ovule. The embryo-sac is very small as compared to the very lariie 

 nucellus. The cells [? nuclei] of the sexual triad resemble one another 

 in all respects ; the three antipodal nuclei increase greatly in number 

 by karyokinetic division during the cell-formation in the endosperm. 

 The pollen-tubes traverse the single thick integument, and find their 

 way between the cells of the cone already described to the embryo-sac, 

 probably through the chemotactic action of the contents of the cells 

 of the cone. Immediately after impregnation the cell-walls of this 

 cone bacome suberised, thus effectually preventing the access of any 

 other pollen-tubes. 



The ovary of Cynomorium coccineum contains two fertile ovules, not 

 one, as usually stated. The authors regard the appendages to the 

 stamens as constituting a true stylodium. They consider that the genus 

 should be removed from the Balanophoraceae, and placed in an order 

 by itself. 



Hybrid Fecundation (Xenia) in Maize. — By the term xenia Fockc 

 designated the influence exercised by the pollen on the hereditary 

 characters of the fruit and the seed outside the embryo. M. H. de 

 Yries ± has demonstrated the occurrence of this phenomenon in the 

 hybridisation of the endosperm of the maize. In hybrid races of 

 Indian corn he shows that every grain in which the endosperm displays 

 the characters of the male parent has a hybrid embryo, and that every 

 grain in which the endosperm shows the characters of the female parent 

 has an embryo of a pure race, and is then self-fertilised. Hybridisa- 

 tion of the embryo is always accompanied by hybridisation of the 

 endosperm. 



Mr. H. J. Webber § has carried out a long series of experiments on 

 this subject on cultivated varieties of Indian corn. His general con- 

 clusion is that xenia in maize is in all cases caused by the fecundation 

 of the embryo-sac-nucleus by one of tho male nuclei, resulting in the 



* Bot. Gazette, xxix. (1900) pp. 408-18 (2 pis.)- 

 + Atti r. Accad. Liacei, ix. (1900) pp. 150-3. 



+ Rev. Gen. de Bot. (Bonnier), xii. (1900) pp. 129-37 (1 pi.). Cf. this Journal, 

 ante, p. 217. 



§ U.S. Deptint. Agric. (Div. Veg. Phys. & Path.), Bull. No. 22, 44 pp. and 4 pis. 



