354 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Germination of Ximenia americana.* — M. E. Heckel records a 

 peculiarity in the germination of this species of Olacine® from the 

 French Congo. Near the insertion of the petioles of the hypogseous 

 cotyledons the stem bears two small linear scales which display positive 

 geolropism, and penetrate between the cotyledons; they become con- 

 crescent with the petioles of the cotyledons, the embryo being imbedded 

 in a copious oily endosperm. The author regards these structures as- 

 being of a foliar character, with the function of assisting the embryo in. 

 absorbing and digesting food-materials from the endosperm. 



Excretion of Water by Leaves-t — Herr A. Nestler has continued 

 his observations on the conditions under which drops of water are 

 exuded by leaves, in the examples of Phaseolus multiflorus and various 

 species of Malvaceae. In all cases the water so exuded is found to con- 

 tain potassium carbonate, a substance which eagerly absorbs moisture 

 from the atmosphere. It is probable that the potassium salt also attracts 

 water from the epidermal cells of the leaf. 



Expulsion of Air from Detached Parts of Plants.* — From experi- 

 ments on the annulus of ferns, sporanges of Equisetum, elaters of Hepa- 

 ticae, &c, Herr C. Steinbrinck has established the fact that even air of 

 the ordinary atmospheric pressure can, under certain circumstances, be 

 rapidly expelled from water. 



(3) Irritability. 



Influence of Various Factors on Circumnutation.§ — Herr C. 

 Fritzsche has confirmed, by a series of experiments, Darwin's and 

 Wiesner's general conclusion that, when the influence of external factors- 

 — light, gravitation, temperature, injuries, &c. — is excluded, the circum- 

 nutation of the apex of a shoot describes a very irregular curve. This 

 was found to be the case with seedlings of Avena sativa, Hordeum di- 

 stichum, Triticum sestivum, Zea mais, Lwpinus luteus, Cucurbita pepo, 

 Brassica napus, and Trifolium pratense ; only with seedlings of Helianthus 

 annuus and sporangiophores of Pbycomyces nitens did the curve approach 

 an ellipse. The curve described by circumnutating roots — Zea, Cucur- 

 bita, Helianthus, Phaseolus — was always an irregular one. 



C4) Chemical Changes (including Respiration 

 and Fermentation). 



Formation of Proteids in the dark in Germinating Wheat. || — 

 According to Herr J. Goldberg, the processes which go on in the em- 

 bryo and in the endosperm during the germination of wheat are quite 

 opposite to one another. While the amount of proteids in the endosperm 

 is continually decreasing, the proportion in the embryo is continually 

 increasing. This can only be the result of the synthesis of albuminoids 

 in the embryo at the expense of amides obtained from the endosperm. 



Production of Alcohol by Plants.^ — M. P. Maze confirms his pre- 

 vious observations on the production of alcohol by plants, especially in 



* Rev. Gen. de Bot. (Bonnier), xi. (1899) pp. 403-8 (10 figs.). 

 + Ber. Deutsch. Bot. Gesell, xvii. (1899) pp. 332-7. Cf. this Journal, 1898, p. 650. 

 X Tom. cit., pp. 325-30. 



§ 'Ueb. d. Beeinflussung d. Cifcumnutation durch verschiedene Factoren/ 

 Leipzig, 1899, 35 pp. and 30 figs. See Bot. Centralbl., lxxxi. (1900) p. 279. 

 || In Russian, Warsaw, 1899. See Beih. z. Bot. Centralbl., ix. (1900) p. 130. 

 \ Comptes Rendus, exxx. (1900) pp. 424-7. Cf. this Journal, 1899, p. 509. 



