_Such as consist of a firm tough matter, disposed into flat and thin
ramifications growing erect, and bearing their scutellæ upon the edges,
surfaces, and at the extremities._
This division comprehends the flat branched tree-mosses of authors;
many of the fourth order of Haller’s lichens; the first part of the
second division of series the second in Dillenius; and the _platisma_
of Hill.
The plants of this division grow upon old trees, especially in thick
and unfrequented woods; some of them upon rocks: they are many of them
extremely common in England upon all kinds of trees. As they were some
of the most obvious, so they were some of the first lichens noticed by
the old writers, by whom they were called _lichenes arborum_.
The mosses of this order were substituted in the room of the _usnea_
in the composition of the _pulvis cyprius_. The very species, which
was most frequently used for this purpose, was the channel-leaved
_lichenoides_ of Dillenius[115], on account of its being easily reduced
into a fine powder, of a good white colour. Nevertheless, others are
undoubtedly as well adapted to the same purposes: and, if it was of
importance enough to employ them to any purposes of the like nature in
our own country, they might be procured in sufficient plenty.
One of the plants of this order is applicable to the same uses as
the Canary-weed, and is reckoned not much inferior to it; and as it
is found in the same places, it is very often packed up with it in
considerable quantities. Dillenius calls it _The flat dyers lichenoides
with longer and sharper horns_[116]. It is truly and properly a plant
of the lichen genus, tho’ the older writers of the last century
called it a fucus. They were led into this mistake by its having flat
ramifications, and from its growing on the rocks by the sea side. It is
found in the East Indies upon trees, and is frequent on the coasts of
the Mediterranean, as well as about the Canary Islands.