ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 93 



also in the mode of germination. Both kinds often form at the period 

 of vegetation one or more bulbous or fusiform roots at the base of 

 the bulb, frequently of great length, the cells of which are filled with 

 water, and furnish a supply of this material to the young plant. 



De Bary's Vegetative Organs of Phanerogams and Ferns.* — 

 This excellent translation of a very valuable work is a great boon to 

 English botanists. It treats in an exhaustive and masterly way of 

 the forms of tissue found in vascular plants (which he classifies 

 under (1) cellular tissue, (2) sclerenchyma, (3) secretory structures, 

 (4) tracheae, (5) sieve-tubes, and (6) laticiferous vessels) ; the primary 

 arrangement of these forms of tissue ; and the secondary changes 

 produced by growth in thickness. The treatment of the vascular 

 bundles is especially new and important. 



;3. PhysiologT-t 



Influence of Light on the G-ermination of Seeds.!— A. Adrianow- 

 sky has made a very large number of experiments with reference to 

 this question. The general conclusion which he draws from them is 

 that diffused light has no influence on the products of germination, 

 but that it retards this process. In all cases he found germination 

 to proceed more quickly in the dark than in full light ; the retarding 

 effect of green light was also very obvious in all the exjperiments ; 

 while all the other results varied greatly in the different experiments. 

 In a few cases germination was even more rapid in violet and blue 

 light than in the dark. As a general result it appears to be the 

 illuminating rays of the spectrum that exercise a retarding effect on 

 germination. 



Effect of Depth of Sowing on the Germination and Growth of 

 Plants. § — There are no definite results obtained by the experiments 

 described by E. Wollny, but the general outcome seems to be that 

 the deeper the seeds or tubers are laid in the soil the more irregularly 

 and the later do the plants appear above ground, and there seems to 

 be a definite depth for each kind of seed ; but this is again dependent 

 on weather and soil. In experiments with rye, it appeared that 

 deeply sown seed suffered much more from winter cold than the 

 shallow sown seeds, and when potatoes are sown deep there is less 

 chance of their being attacked by disease. 



Influence of Water on the Growth of Plants- II —Hellriegel has 

 investigated the questions : How much water does a plant transpire 



* De Bary, A., ' Comparative Anatomy of the Vegetative Organs of the Phan- 

 erogams and Ferns. Translated by F. 0. Bower and D. N. Scott.' 8vo, Oxford, 

 1884. 



t This subdivision contains (1) Eeproduction (including the formation of the 

 Embryo and accompanying processes) ; (2) Germination ; (3) Growth ; (4) Eespira- 

 tion ; (5) Movement ; and (6) Chemical processes (including Fermentation). 



X Nachr. d. Petrowskischen Agricultur u. Forstakad. Moskau, vi. (1883) pp. 

 171-92 (Russian). See Bot. Centralbl., xix. (1884) p. 73. 



§ Bled. Centr., 1884, pp. 293-9. See Journ. Chem. Soc— Abstr., xlvi. (1884) 

 p. 1404. 



II Bied. Centr., 1884, pp. 475-84, See Journ. Chem. Soc— Abstr., xlvi. (1884) 

 pp. 1401-2. 



