RECENT EXPERIMENTS BY DR. MINKS. 
91 
of the most clear-sighted opponents of the algo-lichenic theory, 
has noticed, and unsparingly criticised an assertion of Dr. de 
Seynes, which was not sufficiently well-founded, and which was 
developed during the session of the Clermont-Ferrand Congress 
( Association Franfaise pour Vavancement des sciences , 1876, p. 495). 
“ I permit myself to bring to notice,” said Dr. de Seynes, “ the 
analogy which exists between the tissue of the thick-sided cells of 
the lignicolous fungi and that of the filaments of certain lichens, 
which have appeared to certain authors, on account of their thick- 
ness, or their peculiar structure, to differ from the fungi cells, and 
to overthrow the algolichenic theory. The observations which I 
have just made appear to me to be of such a nature as not to per- 
mit the existence of this objection.” 
Dr. Leveille first (“ Traite de botanique,” by Messrs. Decaisne 
and Le Maout), and more recently M. Th. Brisson (“ Exam. crit. 
de la theorie de Schwendener,” p. 35 and 36), and Dr. W. Nylan- 
der, have pointed out the difference of structure in question. This 
structure exists not only in certain lichens but in all. Dr. Leveille 
has shown the difference which exists between the germinative fila- 
ments of lichens and the fungi mycelium. Why does Dr. de Seynes 
compare other tissues about which there is ho question ? Has he 
established the slightest resemblance of structure between the ex- 
ceptional fungi cells and the ordinary filaments of lichens ? 
Dr. W. Nylander (“Flora,” 1877, No. 23, p. 256), refutes M. 
Tulasne’s observation (“ Memoire Licb.,” p. 20), in which it is 
stated that the cells (gonidia) sprvng directly from the filaments of 
the medulla. The author of the “ Synopsis Lichenum ” declares 
that in no case do the filaments themselves give birth to gonidia. 
“ The latter,” says he, “ have their origin in the parenchymatous 
cortical cells, which are observed on the prothallian filaments of 
germination.” 
This is a contradiction of the new discoveries of Dr. Minks, and 
of other naturalists who have confirmed the facts advanced by him. 
Thus, the microgonidia which are transformed into gonidia, would 
seem to exist, not only in the hypha, but in all the cells of vegeta- 
tion and reproduction of lichens. 
I will sum up in a few words some other observations which, 
from other points of view, are calculated to define the very clear 
separation between the two neighbouring families, and which obser- 
vations Dr. Minks’s discovery decide to be well founded. 
Thecasporous fubgi may be developed everywhere, in damp or 
dark places ; lichens, on the other hand, love plenty of light. 
Fungi are always provided with hyphae, while these are wanting 
in certain species of lichens. 
The anatomical elements of the filaments of lichens may be dis- 
tinguished by numerous characteristics from the hyphaj of fungi. 
They are firmer, more elastic, and may be at once recognised in the 
texture of lichens, and by the lichenin which may already be seen 
in the first germ-filaments. On the other hand, the hyphae of 
