80 Prof. H. Karsten on the Fecundation of the Fungi. 



the distinction between asco- and basidiospores, aud^ in my 

 opinion, increases the difficulty of understanding the develop- 

 ment of the latter, consists in the fact that the spores of the 

 Lichens and Ascomycetes are produced in a simple regular se- 

 quence of endogenous cell- development from the one fecundated 

 oviceil, and only the last generation qf the spore mother cells is 

 slightly produced downwards in a peduncular form, becoming 

 united with the subjacent tissue in the Basidiomycetes ; on the 

 contrary, a sprouting of the cambial hymenium-cells, which 

 multiply and regenerate themselves for the development of the 

 spores, takes place at a more or less early period of development. 

 By this means, as also by the amalgamation of these superiorly 

 elongated and branched hymenial cells of the Basidiomycetes 

 with the neighbouring tissue of the pileus, the limits of the two 

 tissues (of the pileus and hymenium) are more difficult to recog- 

 nize than in most of the Ascomycetes. 



EXPLANATION OF THE FIGURES. 



Fig. 1. Two naked archegonia of Agaricus vaginatus, Bull. 



Fig. 2. A similar archegonium, and near it a cylindrical branch-cell amal- 

 gamated with it at the point of contact. 



Fig. 3. A young fruit-rudiment, iii the middle of which a large cell is to 

 be seen. 



Fig. 4. The large cell set free. 



Fig. 5. Longitudinal section of an older fruit-rudiment, already covered 

 by the cortical layer, above this central cell. 



Figs. 6 & 7- Two other young but more developed fruit-rudiments. 



