314 SUMMAKY OF CURKENT RESEARCHES RELATING TO 



for seed-dispersion. The calyx may open and close hygroscopically like 

 certain capsules ; the calyx or the carpels may be bladdery, or the 

 involucre, calyx, or carpels may be accrescent to facilitate flight. Wings 

 may be developed on the calyx or on the carpels. Berries occur, and in 

 one case a fleshy calyx. Jerking and clinging mechanisms also occur in 

 the order. 



The author believes that the primitive form of fruit in the Malvaceae 

 much resembled that of Abvtilon. In the course of evolution there 

 occurred on the one hand a tendency towards reduction and fixation of the 

 number of carpels, which remained dehiscent, and on the other a 

 tendency towards reduction of the number of seeds in each carpel, pro- 

 ducing eventually an achene. 



Floral Structure of Juglandeae.* — Th. Nicoloff considers that the 

 male flower of Jiiglans regia is formed on a tetramerous plan, having a 

 perianth of four parts and a pair of bracteoles. A study of the pollen- 

 sac development in Ccerya amara shows that the sporogenous cell only 

 becomes differentiated (by size and richness of contents) after several 

 tangential divisions of the hypodermal cell, so that it is separated from the 

 epidermis by four cell-layers. This is not in accordance with the course 

 <>f development indicated by Warming, in which the sporogenous tissue 

 becomes differentiated after the first tangential division of the sub- 

 epidermal cell. 



The female flower of Juglans regia is formed on the same plan as the 

 male. M. Nicoloff, from a study of the course of the vascular bundles, 

 comes to a result different from that arrived at bv Van Tieghem who 

 assumed that each ovary contained theoretically four ovules. 



In the nucellus of Juglans, two more or less distinct regions were 

 found. One, in the micropylar region, consists of cells which are fairly 

 large and slightly elongated. They are arranged in radiating lines 

 diverging from the base of the embryo-sac. The lower part of the 

 nucellus consists of a central axis of cells which are much longer than 

 broad, and with a somewhat denser protoplasmic cell-content than that 

 of the peripheral layers. 



It is not possible to make out an archesporium, owing to the com- 

 plete transition between the parenchyma of different parts of the 

 nucellus. The embryo-sac has two synergids towards the micropylar 

 region. Very rarely two embryo-sacs occur in the same nucellus. 



The development of the cotyledons and the seed-coat (on which 

 stoma ta occur) is briefly described. 



Physiology.' 

 Nutrition and Growth. 



Photosynthesis outside the Plant.t — L. Macchiati describes further 

 researches which confirm his previous statement that chlorophyll-assimi- 

 lation in plants is the result of the action of an enzyme. A glycerin- 

 extract was prepared from leaves washed in distilled water. The ferment 

 was dissolved in benzine and precipitated by evaporation of the benzine 



* Op. cit., pp. 520-4. 



t Coinptes Rendus, cxxxv. (1902) pp. 1128-9. See this Journal for 1902, p. 72. 



