278 SUMMARY OF CUREENT RESEARCHES RELATING TO 



the fibro vascular bundles. Growth takes place apically from a tetra- 

 hedral apical cell. The larger number of species of Phyllanthus, 

 characterized by phylloclades, grow in moist rather than in dry 

 climates. 



p. Physiology. * 



Excretion of masses of Sexual Protoplasm before and during 

 Impregnation.! — Herr A. Dodel-Port illustrates this phenomenon 

 from a large number of types in both the animal and vegetable 

 kingdoms. 



In the PeronosporesB the male fertilizing substance consists only 

 of idioplasm, the nutrient protoplasm remaining behind; in the 

 female organ the periplasm must be regarded as the analogue of the 

 " excretion-substance " of Uloihrix and Spliseroplea. In the Sapro- 

 legnieae, the author considers that a sexual process takes place, and 

 the excretion of sexual protoplasm is in most cases reduced to the 

 expulsion of water. In the Zygomycetes the separation of the resting- 

 spore from its parent-cells must be regarded as a phenomenon of 

 exoretion. In the lowest sexual stage of vegetable life, the Gamo- 

 sporeae, where conjugation takes place between two similar swarm- 

 spores, as TJloihrix, Acetahularia, Enteromorpha, TJlva, Cladophora (?), 

 &c., the excretion-substance appears to be represented only by the 

 so-called " vesicle " of the sexual parent-cells. 



The AlgEe display a higher stage. In Sjpirogyra Heeriana, during 

 coalescence of the conjugating cells, an excretion of protoplasm always 

 takes place. In Craterospermum and Staurospermum only the chloro- 

 phyll-plates coalesce, while the protoplasmic utricle of the conjugating 

 cells remains behind as useless. In Sirogonium a much more copious 

 excretion takes place, the male cell throwing off two and the female 

 cell one sterile cell. In Sphseroplea the male cells throw off almost 

 the entire nutritive protoplasm, and consist of idioplasm only, the 

 ovum-cell becoming the chief bearer of the nutritive protoplasm. In 

 the CEdogoniese, Vaucheriacese, and Fucacese, the excretion from the 

 protoplasm of the ovum-cell is much more striking ; and in Characese 

 only a portion of the protoplasm of the male cells is used in the 

 production of antherozoids, the rest being excreted as useless. 



In the Archegoniatse we have a still further step. The excretion 

 in the female protoplasm is preceded by a division of the nucleus and 

 the formation of the ventral canal-cell, which may be regarded as a 

 true excretion-substance. In Gymnosperms the whole of the pollen- 

 tube, except the nucleus which enters the ovum-cell, constitutes the 

 male excretion-substance. In the embryo-sac of Angiosperms the 

 daughter-nucleus which moves towards the pole after the first division 

 of the nucleus appears to be the carrier of the female idioplasm. It 



* This subdivision contains (1) Keproduction (including the formation of the 

 Embryo and accompanying processes); (2) Germination ; (3) Nutrition; (4) Growth; 

 (5) Respiration ; (6) Movement ; and (7) Chemical processes (including Fermen- 

 tation). 



t Dodf'1-Port, A., ' Biologische Fragmente,' Part II. (24 figs.). Cassel and 

 Berlin, 1885. See Bot. Centralbl., xxiv. (1885) p. 132. 



