PHYLOGENY 77 
(in Corallina) an arrangement of four superposed cells as in the 
“basidium ” of the Uredinales. Moreover in one of the groups 
of the latter, the Coleosporiaces, as well as in Chrysopsora, this 
division into four cells takes place within the spore-mother-cell, 
not outside it. It is a reasonable tentative hypothesis that 
this “internal” formation of the four cells is the primitive 
mode, inherited from the predecessors of the groups, and that 
the formation of an external “basidium” is a later adaptation 
of their successors to their environment. This would lead one 
to look for the ancestors of the Uredinales among the Red 
Algee. 
The obvious implication is that the Coleosporiacee retain 
much of the Uredinal primitive character, and this is borne out 
by the fact that the ecidial host of Coleosporium is in every 
case, so far as known, a species of Pinus. The teleutospore- 
host may belong to the Composite or varivus other families, it 
is true, but it is now generally admitted that the ecidial host 
is the primitive, and that the others have been adopted by 
successive mutations. It has an important bearing on this 
argument that, in Gallowaya Pini, the teleutospores which are 
of exactly the same nature as in Coleosporiwm are borne on 
a Pine (Pinus inops Ait.). 
Again, it has been shown that‘it is possible, without violence, 
to interpret the female-cells of the ecidium as furnished with 
a trichogyne, such as the carpogonia of the Floridez possess, 
though in the Uredinales (possibly as a consequence of their 
terrestrial habit) it has become abortive. Trichogynes are not, 
uncommon in other groups of Fungi—in certain Ascomycetes, 
in the Laboulbeniacez, and among the Lichens, in Collema and 
other genera. Moreover in Collema the trichogyne and corre- 
lative spermatia are almost certainly functional (Bachmann, 
1912); the same is true in the Laboulbeniacer, but in most 
Ascomycetes the trichogyne has either been lost altogether, or 
if it survives has lost its function. 
In order that the trichogynes in the ancestral Uredinales 
should be effective, the female gametes must have been situated 
beneath a stoma. It is a suggestive fact that in certain of the 
group, belonging to the lowest forms, the sori of various kinds 
