ОЕ А REMARKABLE UREDINE. 145 
In addition to this difference in shape, the peridium filled with teleutospores differs 
also markedly in having а hymenium consisting of long parallel stalks, about 95 и in 
depth, instead of the short basidia of the «cidiospores (Pl. XLIX. figs. 15 and 17). 
SPERMOGONIA.—Spermogonia are present as usual in the early stages of development 
of the first crop of æcidia] patches—that is, those produced by the sporidia ; but they are 
by no means numerous, and soon all traces of them disappear. These structures are 
entirely absent from the patches formed later by the xcidiospores. I have never seen 
them in any of the numerous sections I have made through secondarily produced 
zecidial patches. They are of the usual form and structure, with a tuft of paraphyses 
protruding through their mouths to the extent of about 444. Тһе spermogonium 
measures about 145 и in depth and width. Before these organs are produced considerable 
hypertrophy has already taken place in the host’s tissues. For example, the normal 
thickness of the leaf-blade was іп one case found to be 157 u, whilst in the spermogonial 
stage it was 409°5 и and in the zecidial 567. They are usually borne on the lower or 
convex side of the leaf-patch. 
PreRIpIuM.—This consists of a single layer of cells, each thickened on one side, the 
outer side, and bevelled at the upper and lower ends (Pl. XLIX. figs. 5 and 18). Тһе 
upper bevelled end of each cell overlaps the lower end of the cell immediately above it. 
The cells measure about 26 x 19 и, the thickened outer side being 3 to 4 in depth. 
JEcrDIOSPORES.— These are round, or more rarely oval, pale yellow bodies, abstricted 
serially in rows as usual, and measuring оп an average 16, in diameter. Externally 
they are beset with minute tubercles (Pl. XLIX. fig. 4). When placed in water they 
germinate freely, immediately after ripening, the contents within a few hours becoming 
vacuolated prior to the emergence of germ-tubes (Pl. XLIX. fig. 5). Тһе subsequent 
phenomena are, however, very remarkable, and unlike those of any other secidiospores 
with which I am acquainted. Тһе germ-tube, which is quickly emitted, soon acquires 
the appearance of a promycelium, as in the case of Endophyllum, but does not actually 
assume the character of one, as it never produces sporidia. After the germ-tube has 
attained a length of about 35 и it divides into two nearly equal parts, and each part now 
forms a long sterigmatous branch (Pl. XLIX. figs. 6, 7). That from the upper cell 
emerges almost always from the extreme end of the germ-tube, but sometimes from a 
point to one side of the end; whilst that from the lower cell emerges usually from a point 
a little below the septum. Тһе exact position of this lower sterigmatous branch is, how- 
ever, more variable: it sometimes emerges from a point near the spore, sometimes from a 
point just under the septum. Тһе length of these sterigmatous tubes varies greatly: in 
one case the upper was found to be about 60 w long and 2 p in diameter, while the lower 
one was a little longer. The coloured contents of the spore wander into the germ-tube, 
and the empty spore-walls are then readily seen to be studded with minute tubercles. 1 
carefully observed many water cultivations, but never saw, either there or upon a leaf- 
surface, any sporidia formed at the ends of these sterigmatous branches. These sterig- 
matous branches enter directly into the tissue of the host, and there form another 
mycelium, commencing the life-cycle over again. 
