72 SUMMARY OF CURRENT RESEARCHES RELATING TO 



number of species with uuissxual flowers, and has arrived at the general 

 conclusion, in accordance with that of Klebs, that the production of 

 female flowers is promoted by a copious supply of nutrient substances, 

 that of male flowers by deficient nourishment. While the pruning of 

 the root or rhizome will tend to the production of male flowers, the 

 formation of female flowers is promoted only by increased vital activity. 



Mendel's Laws of Hybridity. — A reprint of G. Mendel's important 

 treatise on Hybridity in Plants — which appeared in the Verhandlungen 

 des naturw. Vereins in Briinn for February 8 and March 8, 1865 (pub- 

 lished in 1866) — appears in the Erganzungsband of Flora for 1901, 

 pp. 364-403 ; and a Translation, with an Introductory Note by W. Bate- 

 son, in the Journal of the Royal Horticultural Society, vol. xxvi. (1901) 

 pp. 1-32. 



Cleistogamy of Stellaria pallida. * — E. Loew regards Stellaria 

 pallida as a clearly distinct species from S. media. The former is a 

 typical cleistogamous plant ; impregnation takes place within the closed 

 flowers, the pollen-tubes fixing the anthers to the stigma ; the corolla is 

 greatly reduced or entirely abortive. In S. media, although the flowers 

 often do not open under unfavourable conditions, the corolla is fully 

 formed, and it is only exceptionally that impregnation takes place within 

 the closed flower. The species is only pseudo-cleistogamous. 



(2) Nutrition and Growth (including Germination, 

 and Movements of Fluids). 



Chlorophyll Assimilation.! — L. Macehiati regards the production 

 of the numerous diastases or enzymes which exist in animals and in the 

 higher plants as a function of the vital activity of tbe living cell. The 

 chlorophyll function of green cells is in all probability the result of the 

 action of a special diastase secreted by the chloroplasts, and the chloro- 

 phyll-pigments under the influence of solar radiation. The phenomena 

 of synthesis (assimilation) and of decomposition (dissimilation) are 

 equally expressions of fermentative processes. The author classifies 

 under seven heads the various modes in which these numerous ferments 

 occur in the vegetable kingdom. Further researches are promised. 



Action of Inorganic Salts on the Structure and Development of 

 Plants.:}: — A series of experiments by G. H. Pethybridge, chiefly on 

 wheat, oat, and maize, leads to the conclusion that growth in distilled 

 water causes very great lengthening of the root, and thickening of the 

 cell- walls of the endoderm and central cylinder. In contrast to a normal 

 nutrient solution, dilution of the solution and the addition of sodium 

 chloride have both a similar effect, viz. : — lengthening of the root, 

 diminution in the number of shoots and in the number of leaves, also of 

 the average length and breadth of the leaf. As regards anatomy, they 

 bring about a decrease in the diameter of the roots, of the vessels in the 

 root, and of the haulm, an increase in the thickness of the cell-walls of 



* Abhandl. Bot. Verein Prov. Brandenburg, xli. pp. 169-83. See Bot. Centralbl., 

 lxxxviii. (1901) p. 172. 



t Bull. Soc. Bot. Ital., 1901, pp. 323-35. 



t Beitr. z. Keuntniss d. Eiuwirkung d. anorganischen Salzen u.a.w., Gottingen, 

 1899, 95 pp. See Bot. Centralbl., lxxxvii. (1901) p. 235. 



