Il IV tJ I*A E IÀ caîcarea.
Calcareous Hivularia.
CRYPTOGAMIA Algoc.
Gen. Char. Frond, gelatinous, firm, destitute of an
external cuticle. Fructification among jointed filaments,
lodged in the substance of the frond.
Spec. Char. Hemisphærical, clustered, sessile, hard,
green. Internal filaments straight, compact, entangled,
simple, with scarcely any appearance of
joints.
S e n t by Dr. Scott from the bed of a river in Queen’s county,
Ireland. We have been informed by several friends that this
singular production is plentiful about many water-falls in
North and South Wales, Shropshire, &c. There can be
no doubt of its ranking as a new species of Rivularia.
The fronds are sessile, round, generally clustered or aggregate,
each as big as a pea, or larger, but often united into an
uneven indeterminate mass. The external surface is of a rich
dark green, slimy to the touch from the fine short superficial
filaments. Internally the mass is paler and brownish, composed
of dense, parallel, entangled, but apparently unbranched,
filaments, of an equal thickness throughout, and, as far as
we can discern, destitute of joints. The whole is impregnated
with a calcareous sediment, from the petrifying nature of the
water in which it grows, which renders it hard, though friable,
and increases the difficulty of detecting the real organization
of its filaments. This calcareous matter, or stalagmite,
is found by itself, in granulated masses, on the adjoining
parts of the stone where this Rivularia grows.