72 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy. 

 (1) Cell-Structure and Protoplasm. 



Structure of the Cell.* — Dr. L. Buscalioni has collected his recent 

 observations (1892-97) on the structure of the cell and cell-nucleus,, 

 together with the results of some more recent researches. The treatise 

 comprises the following subjects: — Development of the endosperm and 

 embryo of Vicia Faba ; Development of the pseudo-cells (Scheinzellen) 

 and endosperm in Lwpinus ; Endosperm of Fritilluria imperialis and 

 Leucojtim vernum ; Latex-cells of ZJriica diuica, U. urens, and Euphorbia* 

 Cyparissias ; Cyanopbily and erythrophily of the nucleus ; Structure 

 and function of the nuch- oles. 



In Vicia Faba the suspensor does not entirely disappear, but persists 

 throughout the development of the seed, and contributes to the forma- 

 tion of the peculiar bodies termed by the author " pseudo-cells." A 

 portion of the endosperm also persists, and is organised into an inter- 

 cotyledonary tissue. The cotyledons finally occupy the whole of the 

 chalazal portion of the embryo-sac, while the radicle and the hypo- 

 cotyledonary axis penetrate into the micropylar portion, almost com- 

 pletely closing it. The pseudo-cells contain a number of large oval 

 or irregular nuclei, which multiply by typical fragmentation. They 

 probably assist in the carriage of nutriment to the embryo. In several 

 species of Lwpinus similar pseudo-cells were observed. No centrosomes 

 were at any time observed. 



In the latex-idioblasts of Uriica, which are only of one kind, three 

 modes of cell-multiplication take place ; karyokinesis, ordinary frag- 

 mentation, and karyoldnetic fragmentation ; in Euphorbia Cyparissias 

 apparently karyokinesis only. 



In a great majority of the endosperm-nuclei of Vicia Faba there is 

 a strong tendency, during the entire development of the seed, to take 

 up green pigments, while the nucleoles are stained red. During karyo- 

 kinesis the nuclei are typically cyanophilons. 



The nucleoles are either homogeneous or contain vacuoles, according 

 to the species and the state of development of the seed. They are almost 

 always separated from the framework of the nucleus by a colourless 

 border. 



There is no connection (in Vicia Faba) between the formation or 

 nutrition of the chromosomes and the disappearance of the nucleoles; 

 nor is there any connection (in Vicia, Fritilluria, and Leucojurn) between 

 the nucleoles and the chromosomes [centrosomes in Bot. Centralbl.] ; 

 while there is a connection between the achromatic threads and the 

 cytoplasm. In Vicia and Fritillaria the nucleoles take no part in the 

 formation of the membrane. 



* Ann. r. 1st. Bot. Roma, vii. (1898) pp. 255-316 (8 pis.). See Bot. Centralbl... 

 Ixxix. (1899) p. 360. 



