ATKINSON: THE GENUS ENDOGONE 11 
zygocarp with a definite and well-developed peridium. This repre- 
sents a distinct progression in development over all other phycomy- 
cetes, a cephalization of zygotes into a complex fruit body. 
The heterogamous character of the gametangia of Endogone lacti- 
flua and the selection of asingle gamete nucleus in each are oomycete 
features. But the lack of differentiation in the cytoplasm in the 
oogone, or gametangia, is a zygomycete feature. For these reasons 
Bucholtz* interprets Endogone as occupying an intermediate position 
between the zygomycetes and Oomycetes, but constituting a distinct 
group, the Endogoneae.’? He probably regards this intermediate posi- 
tion as simply taxonomic, not phylogenetic. 
RELATION OF ENDOGONE TO THE ASCOMYCETES 
Endogone has been shifted in all the three great divisions of the 
fungi. It was first placed in the Basidiomycetes near Rhizopogon by 
Link (1809) who was followed by Fries (Syst. Myc. 2, 295, 1822). 
For a long time it has remained in the Ascomycetes, being placed in 
the Tuberaceae by Vittadini (1831), by Tulasne (1857), by Saccardo 
(Syll. Fung. 8, 905, 1889). Schroeter (1889) placed Endogone with 
some uncertainty in the Order Protomycetes, the highest order of the 
Phycomycetes. He was followed by Saccardo (Syll. Fung. 14, 829, 
1899), and it is significant that the genus Protomyces has by many 
students been placed in the Phycomycetes. In 1897 Schroeter, while 
still retaining Endogone in the Protomycetaceae, transferred the group 
to the Hemiascineae. 
Until we know the morphological and cytological phenomena in 
connection with the germination of the resting zygotes of Endogone 
we cannot say with any degree of precision what relation it bears to 
the Ascomycetes, nor how near that relation is. It appears quite 
probable that Endogone does bear an interesting relation to the 
Protoascomycetes. If the resting zygotes germinate fructificatively 
with free cell sporulation, somewhat as occurs in Dipodascus or 
Protomydes, its relation to the Protoascomycetes would be very clear. 
The question would then arise whether with its coenocytic mycelium 
it should be placed on a level with Dipodascus or just below it, repre- 
senting the highest level of the Phycomycetes. Even if the germina- 
tion phenomena should prove to be of the phycomycete type, Endo- 
4 He describes two large nuclei in the zygote of E. ludwigit, a sexual species. 
5 The genus has been considered for a long time by a number of students to 
represent a distinct family. Fries (Summa Veg. Scand. 1849) proposed the 
family Endogonaceae and in view of Bucholtz’s studies it is interesting to note that 
Schroeter in 1889 placed it along with Protomyces as the highest member of the 
* Phycomycetes. 
