3o8 
THALLOPHFTES. 
species of Fungi, I will simply endeavour to illustrate the characteristics of the three 
principal groups above-mentioned by giving a complete account of such forms 
as have been accurately described by reliable observers, laying especial stress upon 
the more important features of their life-history. 
A. The Ascomycetes. 
In the fructification of the Fungi belonging to this group there arise from the 
ends of the fertile ascogenous hyphae cells of a club-shaped or spherical form (asd), 
from the protoplasm of which numerous spores {ascospores) are developed by free-cell- 
formation ; usually a definite number of these spores, either four or eight, occurs 
in each ascus. The fructifications are either open [apoihecia) or more or less com- 
pletely closed iyperithecid). 
The spores always possess a firm cuticularised external membrane, the exo- 
spore, the surface of which usually presents asperities of different kinds : the inner 
membrane (endospore) of the spore forms, when the exospore has become ruptured 
in germination, the first hypha (or more than one) from which the mycelium takes 
its origin. 
The mycelium produces in many instances conidiophores upon which the 
conidia are developed by abstriction. The conidia generally have a smooth surface 
and a very thin external membrane. In many genera they do not occur, although 
nearly-related genera possess them in abundance : for instance, they are absent in 
Tuber and present in Penicilliuni. In addition to the conidiophores there occur 
beside the fructification or even upon it, certain peculiar receptacles in which larger 
or smaller conidia {Stylogonidia in Pycnidia, Spermaiia in Spermogonia) are developed, 
which, ever since the publication of the important mycological works of Tulasne, 
have been regarded as non-sexual reproductive cells of the Ascomycete upon which 
they exist. Since De Bary has shown that in many cases the pycnidia belong to 
other Fungi which are parasitic upon those in question, there has been some justifi- 
cation for the assumption that the so-called spermogonia also represent distinct 
genera of Fungi ; and this assumption gains in probability when it is considered that 
it deprives the doctrine of the pleomorphism of Fungi of its last remaining support. 
(1) Gymnoascus ^ is one of the simplest of the Ascomycetes. It is a small Fungus 
growing upon horse- or sheep-dung, the mycelium of which developes numerous sexual 
organs. Here the pollinodium and the carpogonium are completely similar before 
fertilisation, but after it has taken place the carpogonium divides so as to form a row 
of cells which grow out into short branched filaments bearing at their ends dense 
masses of asci each containing eight spores. As the investment is quite rudimentary 
the fertile portion of the fructification is in this case naked, and resembles, in this 
respect, that of the simplest Florideae. [Nemalion). 
(2) Discomycetes ^. In order to illustrate as fully as possible the formation of 
^ Baranetzky, Bot. Zeitg. 1872, no. 10. 
2 De Bary, Ueber die Fruchtentwickelung der Ascomyceten, Leipzig, 1863, p. 11. — De Bary 
und Woronin, Beiträge zur Morphologie u. Physiologie der Pilze, 2nd series, pp. i and 82, Frankfort 
1866. — Tulasne, Annales des Sei. Nat. 5th series, vol. VI. p. 247. 1866. — Glinka- Janczewski, Bot. 
Zeitg. 1871, no. 18. [Quart. Journ. Micr. Sei. 1878, p. 438. — Brefeld, Unters, üb. Schimmel- 
pilze IV.] 
