530 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



Structure of the Pericarp of Orchideae.*— J. A. Oesterberg 

 describes tlie structure of the pericarp in a number of plants belong- 

 ing to the order Orchidese, with special reference to the course of the 

 fibrovascular bundles in the flower. The pericarp he states to 

 consist of four distinct portions ; the protecting tissue, the mechanical 

 tissue, the pneumatic and assimilating tissue, and the vascular bundles ; 

 each of which is described in detail. 



Chemistry of Woody Tissues.f — N. Sehuppe confirms the 

 generally accepted chemical composition of cellulose, C^ Hjo O5. The 

 gum which remains after treatment with water, alcohol, and dilute 

 soda he finds to have, in the German and American walnut wood, the 

 composition of cellulose; in the oak and mahogany the formula 

 Cu H,2 On (2Co H,o O5 + Go H, 0) ; in the poplar and alder, CgHu Og 

 (CoH,oO,4-G,H,0). 



The wood-fibre, after extraction of this gum, yields an approximate 

 average composition C 45*4 per cent., H 5-9, O 48-7. The pro- 

 portion of ligniu in various kinds of wood he finds to average about 

 17-62 per cent. ; that of cellulose being about 40*7. For lignin he 

 gives an approximate formula C^ Hig Og, which is also the composition 

 of catechin ; the varying properties of lignin seem to have some rela- 

 tion to the presence of tannic acid. The relative proportion of lignin 

 and cellulose named above would give for the normal composition of 

 wood a formula somewhat resembling 50^ Hjo O5 -)- ^19 Hjg Og. 



First Products of Assimilation.^: — In opposition to the state- 

 ments of Loew and Bokorny, A. Mori still maintains his view as to the 

 formation of an aldehyde as the first product of the mutual decom- 

 position of water and carbon dioxide. He disputes their assertion 

 that a red tint is produced in fuchsine sulphite simply by the evapora- 

 tion of sulphurous anhydride without the application of heat. No 

 trace of coloration was produced by placing two or three drops of the 

 reagent on various substances, such as cotton thread, cotyledons of 

 the lupin or scarlet runner, &c. 



Selective Power of Absorption of Roots. § — Herve Mangon 

 records a remarkable instance of the power of plants to absorb 

 different proportions of the constituents of the soil under different 

 circumstances in the case of the ice-plant, Mesemhryanthemum crystal- 

 linum. The strongly refractive glands on the surface of the leaves 

 contain a very large amount of saline ingredients. In these he found 

 the percentage of chlorine in the ashes to vary between 5*4 and 

 12 • 1, of potassa between 11-1 and 18 • 7, and of soda between 4 • 4 and 

 10-3. 



* Bot. Gesell. Stockholm, March 7, 1883. See Bot. Centralbl., xiv. (1883) 

 p. 125. 



t Sehuppe, N., ' Beitra2;e zur Chemie ties Holzgewebes,' 39 pp., Dorpat, 1882. 

 See Bot. Centralbl., xiv. (1883) p. 105. 



X Nuov. Giorn. Bot. Ital., xv. (1883) pp. 203-5. Cf. this Journal, i. (1881) 

 p. 906 ; ii. (1882) pp. 67, 361, 522 ; ante, p. 225. 



§ Comptes Reiidus, xcvi. (1883) p. 80. 



