174 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cells. These cells in some instances leave a well-marked path through 

 the cytoplasm. They retain their coiled form for some time after contact 

 with the nuclei, with which they ultimately fuse, one with the oosphere- 

 nucleus, the other with the endosperm-nucleus. Before fusion is com- 

 pleted they become nearly spherical, being slightly flattened on one 

 side. 



Embryogeny of Impatiens and Tropaeolum. * — C. Brunotte has 

 studied in detail the anatomical structure, and especially the develop- 

 ment of the embryo, in these two genera. The polymorphism of the 

 leaves, and the variations in the conformation of the embryo, offer a 

 strong contrast to the uniformity in the structure of the flower. The 

 lateral nectariferous appendages of the petiole are wanting only in 

 Impatiens noli-tangere. This species differs also from the others of the 

 genus in the abortion of its terminal root, its place being supplied by a 

 second whorl of four lateral roots. 



The rudiment of the radicle of I. noli-tangere is limited by a simple 

 primitive epiderm, like that of the hypocotyl of which it is a prolonga- 

 tion ; and this epiderm covers not merely a group of four initial cortical 

 cells placed side by side, as in I. Balsamina, but four or five layers of 

 nearly similar cells. In Tropseolum the mantle of 10-15 layers of cells 

 which surrounds the epiderm is not, as has been supposed, an epidermal 

 portion of the embryo ; it represents, in fact, the enlarged basal portion 

 of the suspensor, which is greatly elongated, and dilated at its lower 

 end, into a parenchymatous projection. 



Fertilisation of Stylidiacese.f — In a detailed account of the structure 

 of this small order, G. P. Burns discusses the cause and the purpose of 

 the remarkable motions of the gynostemium in the open flower. The 

 sudden movement is caused by unequal growth and by the arrest of this 

 rapid growth. It may take place spontaneously, but only by night 

 and with a high temperature, and the result is then to bring the anther- 

 lobes into contact with the stigma. But it is usually brought about by 

 the irritation of visiting insects attracted by red spots on the labellum. 

 Its effect is then to promote cross-pollination, the pollen being thrown, 

 by the violent bursting of the anther-lobes, on to the back of the insect, 

 and is then taken up, in tho next flower visiter), by the rough hairs on 

 the stigma. After fertilisation there arise in the embryo-sac two large 

 haustoria, each of which contains two nuclei resulting from the division 

 of the embryo-sac nucleus. The embryo is at this time undifferentiated ; 

 the cotyledons are formed only during germination. The observations 

 were made on several species of Stylidium. In two species a mycorhiza 

 was observed. 



Embryology and Fertilisation of Rhopalocnemis. J — Dr. J. P. 

 Lotsy describes the structure of the remarkable Rlwpalocnemis phalloides, 

 a parasite on the roots of different kinds of trees in British India and 

 Java. 



* ' Rech. embryoge'niques et anatomiques sur quelques especes d'Inipatiens et de 

 TroptBolum,' Nancy, 1900, 10 pis. See Bull. Soc. Bot. France, xlvii. (1900) p. 398. 

 Cf. this Journal, 1900, p. 345. 



t Flora, lxxxvii. (1900) pp. 310-54 (2 pis. and 8 figs.). 



X Ann. Jard. Bot. Buitenzorg, xvii. (1900) pp. 73-101 (12 pis.) (English). 



