€84 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including: the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including Cell-Contents. 



Cell-division in (Edogonium.* — Gr. Kraskovits has made a careful 

 investigation of the phenomena connected with this subject, and his 

 conclusions are somewhat different from those of other authors. He 

 finds that the ring is composed of two layers, the central one being 

 formed from the cell-membrane by a process of liquefaction. One zone 

 of the enveloping membrane liquefies and forms the primary substance 

 of the ring. The consequent attenuation of this membrane facilitates 

 the subsequent tearing at that spot. When the primary ring-substance 

 is fully formed, a new membrane is formed along the entire surface of 

 the cell-envelope, and this is thicker in the parts surrounded by the ring. 

 This process occurs in every case of cell-division. The caps and sheaths 

 which are formed by the tearing of the membrane over the ring, repre- 

 sent the remains of the next oldest membrane-layers which were formed 

 in a similar manner. The caps and sheaths are not necessary parts of 

 the cell-unit, and may indeed disappear in some living cells without 

 harm to those cells. The tearing of the cell-membrane over the ring is 

 facilitated by the swelling action of the ring-mucilage, which increases 

 largely in size by the absorption of water. This mucilage takes part also 

 in the formation of the cuticle over the intercalary membrane between 

 the cap and the sheath. In the young germinating plant cell-division 

 may take place with or without ring-formation, depending on the species. 

 In either case the first division of the unicellular plantlet appears to 

 differ from all subsequent divisions in the plan and formation of the 

 inner layer. The author details his method, and gives a list of the 

 reagents employed. His material consisted of plants of 0. crispum, 

 0. Vaucherii, 0. capillars var. nutans, and 0. ceruginosum. 



Chemistry of Fungi.f — C. Gessard has tested the sap of Russula 

 delica, and finds that it contains laccase, tyrosynase, and peroxydase. 

 He has experimented with it on hares, and gets a serum that is anti- 

 peroxydase. 



J. Zellner % gives an account of the various substances he has found 

 in Amanita muscaria. He remarks on the unusual quantity of mannite 

 present in dried fungi as compared with freshly gathered specimens. 



* SB. k. Akad. Wiss. Wien. cxiv. (1905) pp. 237-274 (3 pis.). 



t Comptes Rendus Soc. Biol. Paris, lx. (1906) pp. 505-6. See also Bot. Centralbl., 

 cii. (1906) p. 149. 



X SB. k. Akad. Wiss. Wien. Math.-Nat. Kl., cxv. (1906) pp. 105-17. See also 

 Bot. Centralbl., cii. (1906) p. 150. 



