39 2 Harper.—Sexual Reproduction in Pyronema 
nuclear phenomena in the young ascus as the same in general 
as in other asci and considers that the asci here as in other 
cases are oogonia. He finds, however, no such bending of 
an ascogenous hypha tip and growth of the ascus from its 
penultimate cell as is seen in the Discomycetes. 
De Bary ( 13 , p. 310) puts the group among the doubtful 
Ascomycetes, and believes they must be regarded as greatly 
reduced forms, their only relationship with other Ascomycetes 
being in their hymenia and asci. This latter view seems not 
improbable, and it seems quite possible to homologize them 
with certain stages in the development of the Discomycetes. 
I have already described the relatively independent growth 
of the ascogenous hyphae in the sub-hymenial layer of such 
forms as produce relatively large fruit-bodies like Ascobolus 
furfuraceus. In forms with still larger fruit-bodies such as 
Peziza Stevensonia , and in numbers of other Pezizas I have 
examined, this condition is still more striking. The connexion 
of the sub-hymenial ascogenous hyphae with the ascogonium 
in Ascobolus disappears at quite an early stage. Indeed the 
ascogenous hyphae seem never to be nourished by material 
brought up from the mycelium through the ascogonium, but 
as far as they obtain new food at all to be dependent on 
the vegetative hyphae among which they grow. They are 
parasites on the tissues of the mother-plant just as the 
sporogonium in the Liverworts and Mosses is parasitic on the 
gametophyte generation. If now these ascogenous hyphae be 
transferred to some foreign host-plant they might be imagined 
as continuing their development indefinitely in the tissues 
of the host, producing crops of asci continuously or inter¬ 
mittently with periods of rest, &c. That is, they might 
develop quite as does the mycelium of such forms as Exoascus 
aureus on the poplar for example. The mycelium of the 
Exoasci would, according to this view, correspond to the 
ascogenous hyphae of the Ascomycetes and not to their 
ordinary vegetative mycelia. Sexual reproduction might 
then only occur at long intervals or be entirely suppressed. 
The ascospores, or the conidia produced from them, might 
