Mycological Notes. 
114 
being what Stevens calls “compound” ( i.e . multinucleate) and 
fertilised a large number of male nuclei which passover from the 
antheridium. Further studies by Stevens have shown that a series 
can be traced from the compound oosphere of A. Bliti to the 
ordinary typical uninucleate egg; this has led him to believe that 
the former is primitive, and that both it and the antheridium have 
probably been derived from plano-gametangia by the loss of motility 
of the gametes. 
The resemblance between Albugo and Pyronema is obviously 
further evidence for the possibility of the common ancestry of 
Ascomycetes and forms like the Peronosporaceae. It is clear that 
what is wanted for the elucidation of this question is a thorough 
study of the simpler, and presumably primitive, Ascomycetes. In 
this connection Barker (Annals of Botany, Vol. 17, 1903), has 
lately investigated in detail the development of the ascocarp in 
Mouascus, which seems to be a very primitive Ascomycete possessing 
a simple antheridium and ascogonium, and having, almost without 
doubt, multiple fertilisation. Barker is led to believe that this type 
of fertilisation is primitive also for the Ascomycetes, that Albugo , 
Mouascus and Pyrouema, are all primitive forms ( Sphaerotheca being 
considered as reduced), and that the ancestor of the Ascomycetes 
is to be sought for in a form like Albugo. He would consider the 
ascogenous hyphae and asci which are produced from the fertilised 
ascogonium as an interpolated sporophyte generation, comparable 
with that in Phytoplithora oinnivora, where the oospore on germination 
produces, not zoospores directly, but a short promycelium on which 
later a few zoosporangia arise. It is also possible that the ascus 
can be derived from a zoosporangium in the same way that the 
ascogonia and antheridia are probably derived (through the 
Oomycetes) from gametangia; connecting links have, however, yet 
to be discovered. It is very interesting to note how the most recent 
work tends to return to De Bary’s old view of the relation of 
Ascomycetes and Phycomycetes, though with the curious extension 
involved in the belief in the primitiveness of “multiple fertilisation.” 
V. H. B. 
