ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 93 



Anatomy of Ceratophyllum.* — Herr J. E. F. af Klercker gives a 

 more detailed memoir on this subject. Agreeing witli Haberlaudt, he 

 disputes the statement of Korschelt that the growing point exhibits a 

 single apical cell ; he finds, on the contrary, that the dermatogen 

 divides only by anticlinals, and forms a sharply defined cell-layer. 

 The processes in the embryo-sac which precede and follow impregna- 

 tion were followed out in detail. With the development of the embryo 

 the greater part of the integument disappears ; a small residue re- 

 maining only at the micropyle and chalaza. The embryo has no 

 suspensor. 



Form of the Stem of Dicotyledons and Conifers. f — M. E, Guinier 

 does not consider that the history of annual climatic vicissitudes is 

 recorded in the form of the stem of dicotyledonous and coniferous 

 trees to the extent generally supposed. The areas of the sections of 

 the layer of growth usually increase from the summit towards the 

 base. The thickness of each layer of growth is, to a certain extent, 

 dependent on the preceding layer; and thick or thin layers are 

 disposed in series often corresponding to periods of sixty years or 

 more. 



Formation of Cork. J — Dr. J. K Weiss classifies the various modes 

 of formation of cork under three different types, all of which occur in 

 the Lythrariese, Onagraceae, Hypericaceae, Myrtaceae, Rosaceae, and 

 other families. The author disputes the statement of Sanio, that 

 cork is sometimes formed in a purely centrifugal way. 



Annual Formation of Cork in the Periderm. §— Dr. Gerber has 

 investigated the question whether the formation of cork in the super- 

 ficial periderm of trees is always renewed every year ; and finds that 

 the thirty-one species examined can be classified into the three follow- 

 ing groups : — (1) Corks which maintain an annual increase until the 

 cork cambium dies in consequence of the formation of inner peri- 

 derm, the younger elements differing from the older ones ; or corks 

 with a permanent formation of annual rings. (2) Corks the phel- 

 logen of which forms cells of different kinds at the commencement 

 and end of the first growing period only ; but from the second year 

 only similar cells, alike in all respects to those of the later cork-cells 

 of the first year. (3) Corks which repeat an annual increase, but 

 always composed of similar elements; and therefore not forming 

 annual rings. Numerous examples are given of each kind. 



Pith of Woody Plants.|| — Herr G. Kassner gives the following as 

 the main results of his observations on a great number of trees. 

 The pith of most woody plants is lignified ; its cells retaining their 



* Bih. K. Svenska Vetensk. Akad. Stockholm, ix. (1885) 3 pis. See Bet. 

 Centialbl., xxiii. (1885) p. 345. Cf. this Journal, v. (1885) p. 825. 



t Guinier, E., ' Formes des tiges des arbres Dicotyledones et Coniferes,' 30 pp. 

 (7 pis.). Gap, 1885. See Bull. Soc. Bot. France, xxxii. (1885). Eev. Bibl., p. 180. 



{ SB. Bot. Verein. Miinchen, March 11, 1885. See Bot. Centralbl., xxiii. 

 (1885) p. 367. 



§ Ber. Sitz. Naturf. Gesell. Halle, 1884, pp. 3-8. 



II Kassner, G., ' Ueb. d. Mark einiger Holzpflanzen,' 38 pp. (2 pis.), Svo, 

 Breslau, 1884. 



