[buller] presidential ADDRESS 17 



Micheli regarded cystidia as mechanical props or stays which keep 

 adjacent gills apart in the interests of spore-development and spore- 

 discharge. In the case of the Coprini, this view has been strengthened 

 by the anatomical work of Wettstein, ^ and its correctness for Coprinus 

 atramentarius has been made sufficiently certain by my own researches. ^ 

 To demonstrate the excellence of Micheli's suggestion has taken nearly 

 two centuries. 



As we have now seen, Micheli discovered three kinds of structure 

 upon the gills of Agarics: spores in groups of four, hairs on the gill 

 margins, and cystidia on the sides of the gills; but he failed to observe 

 basidia, sterigmata, and paraphyses; furthermore, his investigations 

 did not extend to the trama. These other gill elements could be 

 brought to light only after the microscope had been considerably 

 improved. 



Micheli was not contented with merely supposing that the little 

 grains which he had found with the microscope were the seeds of fungi, 

 but he performed a series of highly original and carefully thought-out 

 experiments which he called "Observations," to demonstrate that the 

 supposed reproductive bodies are able, as a matter of fact, to give rise 

 to plants of the same species as those which bear them. He made his 

 tests of the seed hypothesis with Agarics, and with three of the com- 

 monest Moulds: Mucor, Botrytis, and Aspergillus, (PI. IV). He 

 planted the spores on a suitable culture medium — dead leaves for 

 Agarics, freshly cut and therefore practically sterile pieces of melon, 

 quince, and pear for the Moulds — and watched the result. The ex- 

 periments with the Moulds came ofï with great certainty and success. 

 A few" days after sowing the spores, a mycelium was produced which 

 in Mucor gave rise to sporangia containing spores, and in Botrytis and 

 Aspergillus developed the characteristic conidiophores bearing spores. 

 The new crops of spores were again sown with results similar to those 

 obtained in the first instance. The experiments were not only repeated 

 but varied in such a way as to afford convincing proof that the so-called 

 seeds really are reproductive bodies. The actual germination of the 

 spores, however, was not observed. The experiments with the Agarics 

 were naturally more difficult to carry out. Fruit-bodies of particular 

 species were allowed to shed their spores on certain kinds of dead leaves 

 which had been carefully chosen. The infected leaves were then placed 

 in the open in heaps, in shady places, where the fungi used for the 

 experiments had never been seen. Some months afterwards the heaps 

 of leaves were carefully examined. In a number of them apparently 



1 R. Wettstein, Zur Morphologie und Biologie der Cystiden, Sitz.-ber. Kais. 

 Acad. Wiss. mat.-naturw. Kl., Wien, Bd. XCV. Abt. 1, 1887, pp. 10-20. 



2 A. H. R. Buller, loc. cit. 



Sec. IV, 1915—2 



