604 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Embryology of Balanophora globosa.* — M. J. P. Lotsy describes 

 tbe remarkable phenomenon of autogamy in this plant. There is no 

 true flower ; but there appears on the axis of the inflorescence a few- 

 celled protuberance, the hypodermal cell of which becomes an embryo- 

 sac, the superjacent epiderm growing out into a long organ resembling 

 a style. The embryo-sac curves ; at each end 4 nuclei are separated in 

 the ordinary way ; but the oosphere and synergids abort, as also do the 

 antipodal nuclei without developing into antipodal cells. There remains 

 only a single nucleus, which divides into two endosperm-cells, of which 

 the lower one gradually disappears, the whole of the endosperm being 

 formed from the upper one. From a cell of this endosperm is developed 

 the true few-celled embryo ; the surrounding endosperm-cells become 

 filled with oil, and the outermost layer, together with the epiderm, 

 developes into a thick-walled testa. 



Embryology of Vaillantia.f — In Vaillantia Jrispida (Rubiaceas), 

 according to Mr. F. E. Lloyd, the archespore consists of about 12 

 cells ; but only one of the megaspores becomes normally an embryo-sac ; 

 this megaspore travelling from the uucellus into the micropylar canal. 

 Fusion of the polar nuclei lakes place at some distance from the ovum- 

 cell, towards which the endosperm moves, and to which it ultimately 

 becomes closely applied. There are three antipodals ; one of them is 

 very long, one end being plunged into the disintegrating archespore. 

 The suspensor forms outgrowths into the endosperm, which act as food- 

 absorbing organs 1 . The endosperm enlarges at the expense of the in- 

 tegument, which has the appearance of a tissue undergoing digestion. 

 A part of the integument persists as the integument of the seed. 



Embryo-sac of Leucocrinum.J — According to Mr. F. Eamaley, the 

 embryo-sac of Leucocrinum montanum is usually nearly spherical ; the 

 polar nuclei fuse before the impregnation of the ovum-cell. The de- 

 finitive nucleus moves from the centre of the sac towards the posterior 

 end before any division takes place. The synergids are large ; they 

 persist for a short time after the fecundation of the ovum-cell. The 

 antipodals do not increase in number, but a fragmentation of their nuclei 

 sometimes occurs. They do not become completely disorganised for a 

 long time. Nothing was observed to suggest a fusion between the de- 

 finitive nucleus and a male cell. 



Ovule of Stangeria.§ — Mr. W. H. Lang finds a close correspondence 

 in the development of the ovule in Stangeria, in the processes of pollina- 

 tion and fertilisation, and in the embryogeny, to those already described 

 by him in Ceratozamia. Two ovules are developed on each sporophyll. 

 The development of the ovule is similar in essential points to that iu 

 Ceratozamia. At the time of pollination the prothallus fills the mega- 

 spore ; the sporogenous tissue is represented by a single persistent layer. 

 The pollen-tubes penetrate the nucellus as in Cycas and Zamia ; in the 

 free end of each two spermatozoids are formed. The snermatozoid is of 



* Ann. Jard. Bet. Buitenzorg, xvi. (1899) pp. 174-86 (4 pis.). Cf. this Journal 

 1898, p. 55o. 



t Pioc. Amer. Ass. Adv. Sci., xlviii. (1899) p. 229. Cf. this Journal, 1899 v 411 



X Tom. cit., p. 289. 



§ Ann. of Bot., xiv. (1900) pp. 281-306. Cf. this Journal, 1898, p 9-1 



