172 LEAF AND SEEDLING DISEASES 
resembles the promycelium of the rusts or smuts, and, as in 
the latter group, it may give rise directly to hyphae, instead 
of conidia, under suitable cultural conditions. Infection of 
trees in the spring is brought about by conidia borne by 
similar conidiophores on needles which have lain on the 
ground during the winter. 
As a remedial measure Mer suggests picking off the dead 
needles a short time before the normal leaf-fall in the 
autumn. It is not impossible to treat nursery plants in 
this way, as the diseased needles are readily detached by 
drawing the hand along the branches. Needles which have 
already fallen form small heaps on the ground, which can 
be cleared up. 
This fungus is apparently the same as that described by 
Hartig (1899) under the name of Allescheria laricis (R. 
Hartig) (= Hartigiella laricis, Lindau, in Engler and Prantl, 
Die natiirlichen Pflanzenfamilien). According to Hartig, the 
disease is common in Germany, and may attack the needles 
of larch trees, especially in nurseries, as early in the season 
as May and June. 
Hypodermelia laricis (Tubeuf). This needle disease, which 
was described by Tubeuf in 1895, is found chiefly in Bavaria 
and the Tyrol, but has not, as far as I know, been reported 
from elsewhere. When attacked by this fungus, some or 
all of the needles of a dwarf shoot turn pale brown, but 
remain attached to the tree. Entirely brown dwarf shoots 
are often quite a conspicuous object on twigs whose needles 
are otherwise green. Bright black apothecia appear on the 
upper side of the needles, forming a single line of elongated 
dots. The apothecia contain asci, which are about 110» long 
and contain four hyaline, unicellular, club-shaped spores, 
66 X 6, with a gelatinous membrane. Interspersed among 
the asci, but shorter than these, are simple hyaline fila- 
mentous paraphyses. The disease is found particularly on 
the lower branches, and does not seriously interfere with 
the growth of the trees. 
The larch needle-rusts. There are two genera of rusts 
which grow on larch needles, both of which have been 
found in Britain, though they are much more common on 
