LEAF AND SEEDLING DISEASES 171 
it is recommended that they should be underplanted with 
beech, after sufficient thinning has been made to enable 
the beech to grow. As the beech is deciduous, the diseased 
needles fall through it and winter on the ground. In the 
following spring the young beech foliage acts as a screen, 
which prevents the free circulation of the ascospores to the 
larch above. This treatment has proved very effective in 
some woods at Freising near Munich. 
Meria laricis (Vuillemin). This is another fungus which 
causes the browning and fall of the needles. The disease 
was first described by Emile Mer (1895), who noted it in 
1890 in a nursery near Nancy. The attacked plants were 
two or three years old, and in June many of the leaves; 
especially on the lower branches, turned yellow. Later the 
yellow colour slowly gave way to brown, beginning at the 
tip. The disease spreads all through the summer and 
attacked leaves may fall as early as July, though they 
generally remain attached to the trees until within one or 
two months of the normal leaf-fall. This disease is par- 
ticularly frequent in nurseries, but may be found in planta- 
tions, especially on small trees 6 to 10 ft. high. Such trees 
are generally attacked on their lower branches, and the 
comparative immunity of larger trees is probably due to 
their branches being too far from the ground to be attacked 
by the conidia. 
The fungus was worked out by Vuillemin (1896), who 
created the new genus Meria to receive this single species. 
Together with Hypostomum Flichianum (another new fungus, 
which he described, on the needles of Pinus austriaca and 
P. montana) he placed Meria laricis in a new family, the 
Hypostomaceae, which he considers to be closely related to 
the Ustilagineae, or smuts. The hyphae which grow in the 
larch needles are septate, branched, and have mucilaginous 
sheaths. Conidiophores, which arise very soon after infec- 
tion, grow from mycelial masses just inside the stomata, 
and emerging through the stomatal pores, divide by three 
septa into four segments. Each segment bears a single 
sterigma, at the end of which a colourless conidium is 
developed, 8-10 Xx 2:6-2:74. This conidiophore closely 
