ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
557 
Prof. Kienitz-Gerloff* comes to the same conclusion as the two 
other observers, summing up his criticism on Plateau’s results with the 
remark that what is new is not true, and what is true is not new. 
Herr Tiebe,f while agreeing in the main with the conclusions of 
Muller and Lubbock, points out that Plateau has, after all, made a 
useful addition to the controversy in insisting on the important part 
played by scent in the attraction of insects. 
Pollination of Cistns.J — M. C. Gerber points" out that in Cistus 
albidus , immediately after flowering, the calyx (with the involucre formed 
of the two so-called outer sepals) completely closes round the pistil and 
stamens, forcing the open anthers on to the stigma, and thus ensuring 
self-pollination. The large size and bright colour of the flowers are, 
therefore, not here a contrivance for attracting insects and ensuring 
cross-pollination. 
Pollination of the Cactaceae.§ — M. L. G. Seurat points out a re- 
markable difference between the floral biology of Opuntia and Cereus. In 
Opuntia the flowers are expanded for many days, and the stamens are 
endowed with a well-marked irritability. The flower is cross-pollinated 
by the agency of bees. In Cereus the flowers remain open only for a 
very short time, and the stamens are quite immotile. They may be 
pollinated by insects, but the part played by them is very much less 
important than in Opuntia. 
Parthenogenesis in Antennaria. — Dr. H. 0. Juel|| confirms the 
observation of the late Dr. Kernel* v. Marilaun of a production of fertile 
seeds in Antennaria alpina without impregnation. The male plants are 
very rare, and produce no functional pollen-grains. In the earliest 
stages, up to the production of eight nuclei, the divisions of the embryo- 
sac exhibit nothing special. From the antipodals a parenchymatous 
mass of cells is formed at the upper end of the embryo-sac. The position 
of the oospheres and synergids is normal. The two polar nuclei become 
closely attached, but do not coalesce. The oosphere then elongates, 
divides, and developes into an embryo without any access of a pollen- 
tube. The polar nuclei then separate, divide, and produce the endo- 
sperm, which is subsequently reduced to a single layer of cells. 
Mr. E. L. Greene ^ calls attention to the production of fertile seeds 
without impregnation in A. plantaginifolia. 
(2) Nutrition and Growth (including- Germination, and Movements 
of Fluids). 
Influence of Nutrition on the Evolution of Plants.** — M. A. Dan- 
geard traces the origin of the differentiation between animals and plants 
to a difference in the mode of nutrition. With a sphere the proportion 
between surface and contents increases with the decrease of radius ; the 
smaller the cell, the larger are the contents in proportion to the size 
* Biol.’Centralbl., xviii. (1898) pp. 417-25. f Tom. cit., pp. 465-9. 
t Comptes Rendus, exxvi. (1898) pp. 1734-7. 
§ Rev. Gen. de Bot. (Bonnier), x. (1898) pp. 191-2. 
|| Bot. Centralbl., Ixxiv. (1898) pp. 369-72. 
M ‘ The Plant-World,’ i. (1898) p. 102. See Bot. Gazette, xxv. (1898) p. 376. 
** Le Botaniste, vi. (1 898) pp. 1-63. 
