ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 669 



greatly assisted by a structure which the author calls, after its discoverer, 

 " Bianeoni's plate " (lamina del Bianconi), common to most tendrils, 

 including all the Cucurbitacere. It consists of a plexus of sclerenchy- 

 matous fibres near the fibrovascular bundles, on the side towards tho 

 concave face of the organ. 



Motile Cushions of Robinia and Porlieria.* — E. Pantanelli describes 

 in detail the structure of tlie motile cushions in the leaves of Robinia 

 pseudacacia and Porlieria hygrometrica. With regard to both the pri- 

 mary and the secondary cushions, he states that, in both the upper and 

 the lower half of the cushion, the expansive force increases as the night 

 advances, diminishing again with the increase of light in the morning. 

 The maximum expansive force in the night, and the minimum expansive 

 force in the day-time, account for the nyctitropic movements of the 

 leaves and leaflets in these species. 



Sensitive Style of Arctotis.f — M. von Minden describes the pheno- 

 mena connected with the sensitive style of two species of Arctotis 

 (Composites, Cynareae), A. a$pera and calendulacea, from South Africa. 

 The pollen is pushed out by the growth of the style, but the very 

 strong proterandry renders self-pollination impossible. The elonga- 

 tion of the style and the opening of the five corolla-lobes take place 

 with very great rapidity. The style is sensitive on all sides, and 

 bends in any direction at an angle of 45°, either as a response to 

 mechanical irritation, or spontaneously under the influence of sunlight. 

 When fully carried out, this curvature of the style brings the stigma 

 into contact with the receptacle. Subsequently the style again con- 

 tracts, so that it and the stigma are almost entirely enclosed within the 

 dried-up anther-tube. The author assigns as the purpose of this 

 irritability the facilitating of cross-pollination by flies. 



Geotropism of Stems.! — Pursuing his investigations on this subject 

 (chiefly on Lupinus albus), E. B. Copeland states that, in nearly all the 

 plants observed, the sharpest geotropic curve occurs above the middle 

 of the hypocotyl. In the base of the hypocotyl the downward curve 

 occurs only in a zone not separated from the root-tip by any mature 

 tissue ; the geotropic response is evidently to a stimulus received at the 

 root-tip. The structure of stems does not demand that the geotropic 

 response they execute shall be negative, and the root-structure is not 

 essential to the positive response ; the more characteristic feature in 

 both organs is the perception. The cotyledon of many Monocotyledons 

 elongates at the base and is positively geotropic, 



(4) Chemical Changes (including: Respiration 

 and Fermentation). 



Appearance and Disappearance of Phosphorus-Compounds.§ — The 

 observations of L. Iwanoff on the appearance and disappearance of com- 

 pounds of phosphorus in plants are in general accordance with those of 

 Schimper. The distribution of phosphorus in plants is very wide ; it 



* Atti r. 1st. Bot. Univ. Pavia, vii. (1901). See Nuov. Giorn. Bot. Ital., viii. 

 1901) p. 524. t Flora, lxxxviii. (1901) pp. 238-42. 



% Bot. Gazette, xxxi. (1901) pp. 410-22 (3 tigs.). Cf. this Journal, 1900, p. 695. 

 § Pringsheim's Jahrb. f. wiss. Bot., xxxvi. (1901) pp. 355-79. 



