120 DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



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connect with it. The question was scarcely ripe for discussion at all before the 

 middle of the present century, for scarcely anything was known of the life-history of 

 the Fungi. Botanists were acquainted with single forms only, and it was known that 

 some of these were reproduced in a like form from spores, as a tree of a distinct species 

 is reproduced from its seeds; hence every distinct form which produced anything 

 that resembled spores was considered to be the complete representative of a species. 

 These form-species and the form-genera composed of them had for the most part only 

 a distant resemblance to non-fungal plants. In the comparative simplicity of their 

 structure they approached nearest to members of the lower groups of Algae, the 

 course of whose development was also then very imperfectly known ; hence the 

 Fungi were always placed next the Algae, but no points of connection were 

 established to show a closer natural affinity between the two groups. But while 

 Ilofmeister's ' Yergleichende Untersuchungen ' were giving a new impulse to the com- 

 parative study of the Mosses and Ferns and of the Algae also, and supplying a number 

 of new points of view, the study of the Fungi was directed into new r paths after the year 

 1851, especially by Tulasne 1 . Starting from a few observations by older writers which 

 had been repeatedly neglected Tulasne undertook to show that the form-species of myco- 

 logists up to that time did not in many cases represent a true species, but that such a 

 form-species might be part with others of the cycle of development of a true species. 

 He showed that a regular succession in time takes place in this development between 

 ihe forms which belong to the species, that, as we now say, the appearance of 

 the successive forms indicates the successive stages in the development of the species. 

 Beginning with the Ascomycetes he extended these views in many publications, 

 which will be cited below, over a large number of different groups of Fungi. 



Tulasne rested his views chiefly, if not exclusively, on the proof of the 

 anatomical continuity of the forms which occur in the fully developed state, of 

 the origin, for example, of the sporophores in question from one and the same 

 mycelium. The sowing and culture of spores under careful management and 

 watching, which were introduced especially by myself, gave us a more accurate 

 acquaintance with the succession of forms. The application of these two methods 

 of investigation has at present resulted in showing 2 that a certain number of groups 

 of Fungi are associated by the rhythm of their development with the main series of 

 the vegetable kingdom indicated above, and approach nearest to the ovigerous Algae ; 

 the stages of their development are homologous with the stages of those Algae from 

 which the Fungi may be phylogenetically derived. To these forms I give the name of 

 Asconiycetous Scries or Main Scries of Fungi, composed of the rhycomycetes, 

 Ascomycetes, and Uredineae. Other groups of Fungi, especially the Ustilagineae and 

 the Basidiomycetes, cannot in the present state of our knowledge be ranked with 

 the Asconiycetous Series, though they connect with certain members of the series 

 as phylogenetically derivative through divergent lateral lines. 



It follows from what has now been said, that to give an account of the course of 

 development of the Fungi we must submit the groups one by one to a comparative 

 examination. This account should begin with the Asconiycetous Scries and include a 



1 Comptes rend., 24 and 31 March 1851, and Ann. d, sc. nat. ser. 3, XV. 

 Heitr. z Morphol. 11. Physiol, d. I'il/c. IV. 



