252 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. 
exhibiting the same comparatively minute specific distinctions, but in which the 
formation of an ascocarp such as belongs to the particular development 
has never been observed, while at the same time there is no reason for considering 
that they belong to any group outside the Ascomycetes. We are compelled by this 
condition of our knowledge to regard these isolated forms as homologous with those 
which are like them and the position of which is known in the course of development 
of other species, and to call them accordingly spermogonia, gonidiophores, pycnidia, 
or the like; it is true that this practice is founded only on probabilities, but it has 
already found its justification in many cases in the strict proofs which have been 
subsequently obtained. Most of the Haplomycetes, Gymnomycetes, Sphaeropsideae, 
&c. of the old systems, one might indeed say all of them that do not belong to the 
groups described in the previous sections, fall in this way and in accordance with the 
present state of our knowledge into the class of Ascomycetes, some connecting 
immediately with well-known ascomycetous species, others through the forms first 
mentioned; the grouping of the very large number of species and particular 
forms is necessarily attended with practical difficulties of a different kind from those 
which are met with in dealing with the few dozen Mucorini or Peronosporeae. 
While referring the reader to the descriptive literature of this subject, it may be 
well to mention a few names in illustration of the above remarks ; most species for 
instance of the old form-genera Naemaspora, Cytispora, Libertella, Septoria, Lepto- 
thyrium, Phyllosticta, Cheilaria, Gloeosporium, Spilosphaeria, Ascochyta, Phoma, 
Diplodia, Myxocyclus, Hendersonia, Sporocadus, Sphaeropsis, Cicinnobolus, Ehr. and 
some others must be classed with the pycnidia and partly also with the spermogonia ; 
species of the form-genera Cylindrosporium, Oidium, Dematium, Conoplea, Periconia, 
Cladosporium, Helminthosporium, Macrosporium, Dendryphium, Mystrosporium, 
Brachycladium, Sepedonium, Mycogone, Aspergillus, Verticillium, Polyactis, Botrytis, 
Fusisporium, Alternaria, Torula, Isaria, Stilbum, Atractium, Graphium, Melanconium, 
Stilbospora, Steganosporium, Coryneum, Exosporium, Vermicularia, Tubercularia, 
Sphacelia, and many others, whose affinity to undoubtedly typical Ascomycetes is either 
certain or very probable, go with the, filamentous gonidiophores and open gonidia- 
bearing hymenia. To these may be united with the needful reservation a large number of 
forms, in which the mycelium and the formation of spores, which must be considered 
homologous with the gonidia, are all that is at present known. Some of these forms do 
actually belong to the above form-genera, for the determination of these genera was made 
to rest on certain particulars of conformation which in some cases appear to our present 
knowledge to have been very superficially examined, and which, as we have since 
learnt, may occur in very various genetic connections. For instance Oidium leuco- 
conium, Desm. and O. erysyphoides, Fr. are names for the gonidiophores of Erysipheae. 
Oidium fructigenum, Kze. and O. lactis, Fres. are somewhat similar forms which do 
not belong to the Erysipheae and whose genetic affinities are quite unknown ; Botrytis 
cinerea is the name of Sclerotinia Fuckeliana when it produces gonidia; B. Bassii 
denotes an isolated gonidial form by no means closely related to the last-named 
Botrytis. Other forms of this series are so widely different from those named above 
that the old describers gave them distinct generic names; thus they called their 
Hyphomycetous forms Arthrobotrys, Gonatobotrys, Haplotrichum, Cephalothecium, 
Stysanus, &c. &c. 
These forms are for the present arranged with the Ascomycetes, because from 
what we know of them they appear to have more connection with that division 
than with other Fungi; but they are only known to us under one form, which may be 
considered to be that in which they produce gonidia. 
