132 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. 
the fact that the two forms were most certainly homologous. This was the case in 
the Mucorini ; see Brefeld, Schimmelpilze, IV. 141, and sections XLI-XLIV below. 
It is then quite clear that only the homology and not the mode of origin determines 
the nature of the structure in this case, and that conidia may be formed endogenously 
and even in an ascus, as well as acrogenously. On these grounds Fries’ venture in 
terminology is not a happy one, and it would be desirable to discard the word 
conidium and employ gonidium in its stead. The confusion pointed out above would 
thus be avoided, and homologous structures would be named alike with one generally 
applicable name in Fungi and in all other plants. We need not at the present day 
trouble about the special terminology of the Lichens, in which the word gonidium has 
hitherto had a special meaning, because as there used it is not only superfluous but 
objectionable, as will be shown in Division III. Moreover its application in the sense 
explained above is only a restoration of the meaning which its author Wallroth 
intended to give it, though under a misunderstanding of the facts. 
For further details on this subject the reader is referred to Tulasne’s Carpologie, I. 
chapter VI. 
Section XXXVI. According to the leading points of view here indicated and 
the present state of our knowledge a review of the course of development of the 
several groups of the Fungi arranges them in the following manner :— 
I. SERIES OF THE ASCOMYCETES. 
Peronosporeae (with Ancylisteae and Monoblepharis). 
Saprolegnieae. 
Mucorini or Zygomycetes. 
Entomophthoreae. 
Ascomycetes. 
Uredineae. 
Cr 
II. GROUPS WHICH DIVERGE FROM THE SERIES OF THE 
ASCOMYCETES OR ARE OF DOUBTFUL POSITION. 
4. Chytridieae. 
8. Protomyces and Ustilagineae. 
9. Doubtful Ascomycetes (Saccharomyces, &c.). 
10. Basidiomycetes. 
Groups ı-4 have been brought together under the name of Phycomycetes 
on account of their close approximation to the Algae. 
Groups 7 and 8 in the second category will be considered in connection with 
the Phycomycetes ; group 9 naturally in connection with 5, and 10 with 6. 

CHAPTER V. COMPARATIVE REVIEW OF THE SEPARATE GROUPS. 
PERONOSPOREAE. 
Section XXXVII. Of the Peronosporeae some species of Pythium live in 
the bodies of dead animals and plants, the greater number as parasites in the tissues 
of Phanerogams, and chiefly in the intercellular spaces of the host, though there 
are species which, like Phytophthora omnivora, also spread through the cells. The 
vegetable thallus consists of copiously and regularly branching tubes, which are 
at first non-septate; but aré divided into chambers at a later time when sexual organs 
