Sexual Organs of Phytophthora erythroseptica , Pethyb. 149 
Such a phylogeny as has been indicated leaves out of account the 
Albuginaceae also. It is likely that they must be derived on a parallel line 
from the Leptomitaceae, which are similar in other ways besides being 
richly provided with periplasm, but which, in the species Araiosporapulchra 
(King, 20 and 21) at all events, have a uninucleate oosphere. There is no 
reason, however, why Albugo Candida should not be the lowest member of 
a series which culminates in A. Portidacae . Stevens (35) has given reasons 
to show that multinucleate fusions are primitive, but this is by no means 
always the case. The Zygomycetes, where multinucleate fusions are the 
rule, have progressed farther from their original algal ancestors than have 
the lower Oomycetes; and it is certain that the lower Ascomycetes, in 
which multinucleate fusions also occur, are a step in advance of both. 
Of the relationship of the genus Phytophthora , Pethyb., to Nozemia and 
to Pythium nothing can be said until species of the last two genera be 
examined as to the development and cytology of their sexual organs. 
It is hoped to do this in the near future. It has been shown that Phyto¬ 
phthora and Pythium are very closely related, and it is equally certain on 
other grounds that Nozemia is very close to both. From considerations of 
its, on the whole, less specialized parasitism one would be inclined to expect 
it to go between the two. Looked at from the point of view of its sexual 
organs it is difficult to see how it can provide a link to connect Phytophthora 
to any form at present known. After much consideration of the matter the 
writer must acknowledge to being unable to find any similarity in the form 
of the sexual organs of P. erythroseptica to those of any other Fungus or 
Alga, near or remote; or any particular reason why they should be formed 
in that way; or any advantage in it. The Fungus itself gives no clue to its 
relationship. Particular attention was paid to the question whether or not 
fruit bodies of the normal type are ever formed, and the author is convinced 
from the examination of a more than usually large number of specimens 
that they never are. It is equally likely that no approach to the Phyto¬ 
phthora type will be found in the Nozemia group, although Hartig (19) in 
his description of Nozemia Fagi figures what was in all probability an 
amphigynous antheridium (see his Fig. 24 b x 1. c.) among many of the 
paragynous type. He, however, did not interpret it as such. 1 Working as he 
was with pieces of naturally infected beech seedlings, it is at least possible 
that this drawing was made from another Fungus which happened to be 
present. Provisionally it is necessary to regard Phytophthora as a strangely 
aberrant form which, having its origin somewhere near Pythium , has 
1 1 . c., p. 49: * Ausnahmsweise und zwar vielleicht dann, wenn in nachster Nahe des inter- 
cellularen Oogoniums kein anderweites Mycel sich findet, von dem aus die Entwicklung des 
Antheridiums erfolgen kann, schwillt der Qogonientrager unmittelbar unter dem Oogonium blasig an 
und wird direct zum Antheridium, wie Fig. 24 b zeigt. So deute ich wenigstens die zuweilen 
aufretenden Stellungen des Oogoniums auf dem Antheridium selbst.’ 
