1062 REPORT— 1898. 



exactly how far it is a constant process. In CEdogonium the germinating oospore 

 forms four zoospores — a process which does not occur again in its later life. The 

 manner of germination is not absolutely indispensable, since the oospore also passes 

 over directly into a filament, though it appears to be the commoner case. Still 

 more peculiar is the germination of Cokochade as described by Pringsheim, in which 

 the fertilised ovum divides and forms a tissue, from the cells of which zoospores 

 arise, which then grow on into the typical thallus. There are no exact investi- 

 gations whether this kind of germination is a constant phenomenon, since the 

 germination has only been observed by I'ringsheim, under conditions which were 

 apparently not very favourable. The formation of these bodies, which are like the 

 zoospores formed elsewhere, from the tissue of the oospore, is perhaps a quite 

 fortuitous circumstance, which differs in no way from the usual propagation. But 

 the chief reason for comparison with the Mosses, and for the assumption of an 

 alternation of generations, lies in the production of specially formed propagative 

 cells from the oospore. It might be quite possible that the cells of the oospore in 

 Coleochcete scutata should pass over directly in to the thallus, but in C. puicinata 

 perhaps only after a change in the mode of growth. The essentially regular germi- 

 nation by help of a pro-embryo, as in Chara, will not be accepted as a formation of 

 a special non-sexual generation. It is true that Vines has advanced such a con- 

 ception, and compares the pro-embryo of Chara with the whole sporogonium of the 

 Mosses. His view has not been taken up, since as a matter of fact in Chara a. 

 comparison seems permissible only with the protonema of the Mosses, or with the 

 pro-embryo of Batrachospermum. 



Next to Coleochate it is the Ascomycetes and Floridese, the life history of 

 which has since the time of Sachs been compared with the alternation of genera- 

 tions in the Mosses, for in both the fertilised ovum has often a complicated develop- 

 ment of its own ; the last object of this is the formation of spores, which are 

 clearly different from the usual propagative cells. As described by Schmitz, and 

 according to the latest observations of Oltmanns (1898), the nature and method 

 whereby the formation of the fruit depends on an intimate union of the fertilised 

 egg-cell with definite auxiliary cells of the mother-plant is extremely peculiar. 

 In the higher differentiated forms, e.g. Callithamnion, according to Oltmanns, a 

 cell-derivative from the fertilised egg-cell — a cell-nucleus with some protoplasm — 

 is united with a large auxiliary cell, and coalesces with it into a new cell-unit, 

 whereupon the nucleus of the auxiliary cell is pushed aside as apparently function- 

 less. This new cell, of which the wall and of which the plasma belong for the 

 most part to the mother-plant, is stimulated by the ' egg-euergid ' to form the 

 spores. In still more highly developed forms the mother-plant provides also for 

 the enveloping of the spore-producing cells. Oltmanns compares the relation of 

 egg-cell and mother-plant with that of a parasite and its host-plant, and sees therein 

 a confirmation of the view that the fruit of the Floridere corresponds to the sporo- 

 gonium of the Mosses. But one may also designate the state of the facts with this 

 expression : that the fruit of the higher Floridese is a product of the mother-plant 

 that is stimulated by the fertilised egg-cell. Pringsheim, at least, might, in the 

 far-reaching dependence of the fruit formation upon the mother-plant, tind a sub- 

 stantial support for his view, that the fruit of the Floridese has not the value of a 

 special non-sexual generation. Finally we have to consider subjective interpreta- 

 tions. I mvself should hold the comparison of the Floridean fruit with the sporo- 

 phytes of the Mosses as quite -justified. But one essential point in this matter 

 ought not to be forgotten. One may compare the fruit of the simple Floride^ 

 with that of the simple Liverworts, and apprehend both as in some degree analo- 

 gous structures. But a very important and interesting difference discloses itself, 

 if one follows up the line of development in the two series. In the Mosses the 

 effort is distinctly marked in the ascending series of forms to diHerentiate more 

 highly the sporogonium as an immediate product of the fertilised ovum, and to 

 make it more independent of the mother-plant in its nourishment. In the series 

 of the Floridea3 the opposite tendency shows itself to make the development of the 

 fertihsed ovum constantly more strongly dependent on the mother-plant, and to 

 attain the higher difierentiation of the fruit by means of essential co-operation of 



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