ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 651 



4. As respects the number of apical cells, Eleoeharls palustris has 

 only one ; while the Marattiaccaj have four. Phanerogams most 

 often have several, not unfrequeutly four. In not a few cases, and 

 especially among conifers and in some Leguminosaj, the line of growth 

 takes a peculiar course. At the apex is a column, the rows of colls 

 which constitute it running parallel to one another and to the axis. 

 This structure is regarded as indicating a transverse meristem 

 composed of equivalent cells. 



5. When distinct histogens occur in the apex, the walls which 

 sejiarate them are as thin as those of the histogen itself. Even 

 roots, therefore, possess a special meristem from which branches 

 proceed in two directions having no genetic connection with one 

 another. 



Pitchers of Dischidia Raffiesiana.* — M. Treub describes the 

 pitchers of this epiphytal liane, belonging to the Asclepiadefe, which 

 is rarely seen in Europe. The pitchers are seated on short axillary 

 branches in pairs or opposite to very rudimentary leaves, and are 

 themselves metamorphosed leaves, exactly resembling the ordinary 

 leaves in their earlier stages. In contrast to Sarracenia and Ne- 

 penthes, the outer side of the pitcher corresponds to the upper side 

 of the normal leaves. The whole of the plant with the exception 

 of the stomata, is covered with a close coating of wax, which extends 

 even to the inside of the pitchers, and seems to preclude the 

 possibility of these being organs of nutrition. They contain water, 

 due apparently partly to rain, partly to transpiration. The only 

 animals found in them were ants, which were always alive. Many 

 of the pitchers were penetrated by the abundant adventitious roots ; 

 and the only function winch could be suggested for them was the 

 accumulation of water, which is conveyed to the plant through these 

 roots. 



Influence of Light and Air on the Anatomical Structure of 

 Plants. | — J. Vesque and C. Viet give the following as the main 

 results of experiments on this subject made partly in the laboratory, 

 partly in the open air : — 



The combined action of light and of air more or less dry (i. e. of 

 ventilation) is to accelerate the amount of transpiration, and hence 

 (1) to increase the total thickness of the foliage ; (2) to promote the 

 development of palisade-parenchyma, either by the increase in the 

 number of layers of cells of which it is comj^osed, or by increasing 

 the length of the cells themselves ; (3) to promote an increased 

 development of hairs, both in number and in length. 



The authors consider that these effects are produced not by one 

 only of the agents, but by the two combined. 



Respiration of Plants.:}: — E. Godlewski has made a careful series 

 of experiments on the relations between the gases inhaled and exhaled 



* Ann. Jard. Bot. Buitenzorg, iii. (1882) pp. 13-37 (3 pis.). See Bot. Centralbl. , 

 xi. (18S2) p. 57. 



t Ann. Sci. Nat. (Bot.) xii. (1SS2) pp. 167-76. 



X Denkwiird. Krak. Akad. Wiss., vii. (18S1). See Bot. Centralbl., x. (1SS2) 

 p. 30S. 



