Petch . — The Genus Eudo calyx, Berkeley and Broome. 391 
The open pustule (Figs. 2, 3) is circular, or sometimes oval, -4-1 mm. diam., 
raised in some cases -i mm. above the surface. When it first opens, it forms 
a conical mound, apparently of yellow hyphae. The growth of the under- 
lying central sporiferous hyphae pushes aside this cap, and leaves a black 
disk of spores surrounded by a rather irregular yellow ring. The hyphae of 
the unopened pustule which form the clear yellow sides and converge at the 
top do not bear spores ; they are cemented together by a yellow secretion, 
and consequently, when the pustule opens, the upper part of the yellow 
zone breaks up. The fragments take the form of irregular thin plates, each 
composed of a few layers of parallel hyphae (Fig. 13). The upper part of 
the yellow ring which surrounds the open pustule consists chiefly of these 
fragments, and the ring appears granular under a low magnification. In 
some cases the sides remain intact and form an upright or recurved ‘ pseudo- 
peridium ’, but this is always brittle and more or less covered with loose 
scales. The ring in the majority of specimens is an annulus of fragments ; 
and similar fragments, dispersed by wind, rain, or insects, lie scattered round 
the open pustules. The breadth of the ring varies according to external 
conditions : as a rule, the loose scales are blown or washed away, and the 
yellow ring is very narrow, being only the free edge of the yellow hyphae 
in the substratum (Figs. 4, 5). In order to obtain undamaged specimens, they 
must be developed in the laboratory. This brittle yellow layer surrounding 
the sporophores is one of the chief characteristics of the genus. 
In vertical section (Fig. 7), the fructification is cup-shaped, and sunk 
into the substratum for about 100-150 \x. There is no parenchymatous 
perithecial wall. When the pustule has opened, it consists entirely of erect 
close-set, parallel hyphae springing from the base of the cup. Those in the 
centre are free from each other and form the conidiophores, and are hidden 
by the black spores. The spores do not extend right to the base and there- 
fore the column changes to clear yellow below. The hyphae towards the 
periphery are nonsporiferous, and thus the black central column is sur- 
rounded (in section) by a clear pale yellow zone of varying width, which 
appears at the surface as a yellow narrow ring or wall round the black disk, 
after the loose scales previously mentioned have disappeared. 
In old specimens, the outer layer of the yellow hyphae, i. e. that which 
is in contact with decaying palm tissue, turns black, but the hyphae are 
parallel, not interwoven. When this has happened, the pustule in vertical 
section appears cut off from the decaying host tissue by a black cup, 
unless the section is almost exactly median : the median section shows 
that the black cup is not continuous, but that the yellow hyphae pass into 
the tissues of the substratum through a central aperture about one-third the 
diameter of the pustule. All the hyphae are approximately vertical and 
spring from the central aperture at the base of the cup. 
The spores (Fig. 12) are subglobose or irregularly oval, or polygonal 
