276 NOTES.—ORIGINAL AND SELECTED.
with several sorts of shell-fish, as oysters, mussels, cockles, buntins, crabs,
prawns, red and white shrimps, craw-fish, &c., are there to be caught below
bridge in the river of Thames.
To-day, of course, Thames salmon and oysters have long
been, to a large extent, things of the past.—W. W. Glenny,
Barking.
BOTANY.
Ricciella fluitans in Epping Forest.—This interesting
little Liverwort was growing luxuriantly last autumn in one of
the ponds on Golding's Hill, Epping Forest. The fronds are
dichotomous, narrow, strap-shaped, and from half to two inches in
length. The allies of this genus are usually found on damp soil
or stones, though some species are able to withstand drought.
The terrestrial species have numerous air spaces on the upper
surface of the fronds, and bear root-hairs and thin green scales
on the lower surface. Ricciella fluitans is usually submerged in
water, though some individuals are to be found growing on the
mud around the margin of the pond. The air spaces are
completely roofed over in the aquatic form, but in the case of
plants growing on land, the air spaces are not completely
closed and communicate with the external atmosphere by means
of a small pore. There are no root hairs, and only very small
scales in the aquatic forms, but these structures are developed
considerably when the plants are transferred to a solid sub-
stratum. The fronds also become broader and shorter. The
floating plants are sterile.
I am indebted to Mr. W. H. Pearson for confirming the
name of the species.—Henry Whitehead, Essex Museum of
Natural History.
Birch-tree Disease.—The disease, which destroyed so many
birch-trees, and was so prevalent during the years 1899-1902,
has almost entirely disappeared in the forest area. One now
very rarely meets with a dead birch. The decline was almost as
sudden as the outbreak, for although during the last three
years some few trees were attacked, the injury done was not
great and the trees slowly recovered.
As far as I have been able to observe these remarks apply
equally to the other localities mentioned in the report in the
disease affecting the birch trees in Epping Forest and elsewhere
(Essex Naturalist XI., 273).—Robert Paulson.