ZOOLOGY AND HOT ANY, MICROSCOPY, ETC. 217 



parenchymatous tissue enclosing chlorophyll, and traversed by a few 

 laticiferous tubes. The chromoleucites are of two kinds — yellow with 

 a pigment closely resembling that of carotin or xanthin, and orange- 

 yellow or red. The glands also contain two coloured fluids — one red, the 

 cyanin of authors (turning blue by the action of bases), the other yellow. 



Hairs of the Verbasceae.* — M. G. Lavadoux finds the presence of 

 peculiar glandular hairs to be a constant character of all the indigenous 

 (French) species of the Verbasceaj, and of all the exotic species ex- 

 amined, in addition to the branched, stellate, or candelabra-like hairs. 



j8. Physiology- 



(1) Reproduction and Embryology. 



Embryology of the Calycanthaceae.f — Sig. B. Longo argues in 

 favour of the affinity of the Calycanthaceae with the Rosaceae. The re- 

 ceptacle is axile in its origin ; all the parts of the flower originating on 

 it distinctly from one another. 



In the development of the pollen-grains the tapete has no uniform 

 morphological character ; its significance is simply physiological. It 

 is the nutrient tissue of the pollen-mother-cells ; karyokinesis goes on 

 actively in its cells. The pollen-grain consists of one large vegetative 

 cell with large nuclei and nucleoles, and a small generative cell. 



The embryo-sac is usually the product of several mother-cells or 

 primordial cells, although each of these may develope into an embryo- 

 sac. In any case, only one embryo-sac attains full development. The 

 author regards the existence of a number of collateral cells of the 

 embryo-sac as a constant character of the Rosacea and Calycanthacese. 



Hybrid-Fertilisation of the Endosperm. J — By fertilisation of the 

 endosperm, M. Hugo de Vries understands the fusion of the hindermost 

 spermatozoid (nucleus) of the pollen-tube with the central nucleus of 

 the embryo-sac, as demonstrated by Nawaschin and Guignard.§ He has 

 been able to establish a hybridisation, both of the embryo and of the 

 endosperm, in the case of a variety of Indian corn known as the " sugar- 

 maize " (mats sucre), characterised by the replacement of the starch by 

 sugar in the endosperm. The stigmas of this variety were pollinated 

 from a plant of the ordinary kind, but without preventing pollination 

 from its own male inflorescence. The result was the production of 

 seedling plants in which the spikes consisted of some seeds of the 

 ordinary kind, while some were filled with sugar ; but there were none 

 of an intermediate description. That the embryos, as well as the endo- 

 sperm, were of a hybrid character was shown by sowing the seeds thus 

 produced, and impregnating the female flowers by pollen from the male 

 inflorescence of the same plant. The result was that the seeds thus pro- 

 duced were filled partly with starch and partly with sugar, but again 

 there were none of an intermediate character. Hybridisation, both of the 

 embryo and of the endosperm, was thus established. 



Peculiar Embryo-sac in Peperomia pellucida. || — Prof. D. H. 

 Campbell describes what appears to be a constant peculiarity in this 



* Journ. de Bot. (Morot), xiii. (1899) pp. 216-8 (-1 figs.). 



t Ann. r. 1st., bot. Roma, ix. (1899) pp. 1-16 (2 pis.). See Bot. C'entrulbl., lxxx. 

 (1899) p. 183. X Comptes Rendus, exxix. (1899) pp. 973-5. 



§ Cf. this Journal, 1899, p. 409. ||| Ann. of Bot., xiii. (1899) p. 626. 



April 18th, 1900 Q 



