ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 443 



Etiolation.* — A. D. Selby has experimented upou Persea gratissima, 

 Asclepias incarnata, etc., and finds that, while light seems to exert a 

 stimulative effect upon tissue-diflPerentiation, there is no reason to 

 suppose that it retards growth. 



Lack of differentiation results in prolonged growth of the meri- 

 stematic cells in etiolated plants, which thus increase in length and may- 

 increase in thickness. If etiolation has not proceeded too far, access of 

 hght will induce normal differentiation. The abnormal formation of 

 mechanical tissue in etiolated plants is due to the tensions set by the 

 curvatures which accompany etiolation. 



Influence of Light on Assimilation.f — W. Lubimenko has ex- 

 perimented upon seeds of pea, maize, lupin, etc, and upon Allium, etc., 

 and finds that the assimilation of the stored organic material is in- 

 fluenced by light. Assimilation is at its maximum when the intensity of 

 light is so weak as to be scarcely sufficient for the formation of chlorophyll, 

 and diminishes in proportion to the increase of the light. The maximum 

 quantities of dry material formed as a result of assimilation, correspond 

 to the varying light-intensities, and vary in the different species. 



Fruit-stalk of Cyclamen. | — F. Hildebrand has studied the move- 

 ments of the fruit-stalk in the different species of Gyclamm, and finds 

 that it is of little importance whether there is a simple bending as in 

 C. persicum, or whether there is a two-fold rolling up of the stalk as 

 in other species, so long as the final aim of bringing the fruit earthwards 

 is attained. 



The different movements appear to be a case of useless variation. 



General. 

 Plants of Formosa.§ — J. Matsumura and B. Hayata have published 

 a useful enumeration of Formosa plants, including the Phanerogams 

 and vascular Cryptogams. It is based on previous Uterature, chiefly the 

 " Enumeration of Chinese Plants," edited by Forbes and Hemsley, and 

 Henry's hst of plantsfrom Formosa, together with the results of collec- 

 tions by various Japanese botanists and by U. Faurie, made within the 

 last ten years. These have added appreciably to our knowledge of the 

 flora, but, as can be seen from the accompanying map, at least half 

 the island (mainly the eastern part) remains practically unexplored. 

 The new species are illustrated by good plates. 



CRYPTOGAMS. 



Pteridophyta. 



(By A, Gepp, M.A., F.L.S.) 



Ecology of Philippine Polypodiacese.H— E. B. Copeland writes in 

 much detail upon the comparative ecology of the Polypodiacete which 



* Bull. Torrey Bot. Club, xxxiii. (1906) pp. 67-76 (4 figs.). 

 t Comptes Rendus, cxliv. (1907) pp. 1060-3 (1 fig.). 

 X Ber. Deutsch. Bot. Gesell., xxiv. (1906) pp. 559-62. 



§ Journ. Coll. Sci. Imp. Univ. Tokio, Japan, xxii. (1906) 704 pp., 17 pis. and 

 map. II Philippine Journ. of Sci., Manila, ii. (1907) No. 1, 76 pp. (4 pis.). 



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