[ 7°2 ]
B Y S S U S nigra.
Black Rock B y jfu s.
CRYPTOGAM IA Alga,
Gen. Char. Whole plant confifting of down or
Ample powder. Fructification unknown.
Spec. Char. Filaments branched, matted, powdery,
black. •
Syn. Byffus nigra. Hudf. 6p6. Light/. 1003.
With, v. 4 . 144. Hull. 307.
B. petrsea nigerrima fibrofa. D ill. M ufc. 9 . t. j,
f . 1 8 . D ill, in R ail Syn. 5 7 .
O n fhady overhanging rocks in the Alpine parts of our
bland this ByJJus is often met with. It forms patches of
various fizes, perfectly black, and may eafily be fcraped from
the ftone. When gathered it clofely refembles a piece of felt
fcraped from a hat, both in texture and colour. It confifts of
a mat of fine, foft, though elaftic, branched filaments, often
covered with an equally black footy powder, which is probably
the feed. Yet;> we do not know that this powder is produced
at any particular feafon exclufively. The plant appears to be
perennial, and, from fome remarks we have made in its place
of growth, very long-lived. We have no fpeeimens to decide
accurately what Linnaeus intended by his B, antiquitatis, but
we can fcarcely aflent to Lightfoot’s fuppofition, that he originally
meant our nigra, though he, «or Murray, in S jJi. Veg-
ed. 13, has quoted the figure of Dillenius and defcription of
Weis which belong to it. Lightfoot’s account is taken, with
a little variation, from the author laft mentioned.
Mr. Sowerby found this plant on fand-ftone rocks, near
Tunbridge, in plenty. I have gathered it on the Pentland
hills near Edinburgh, and about Winandermere, Weftmore-
land; but no where in fuch perfection as at Hafod, Cardigan-
fhire, on a fhady rock oppofite the. great ftone of Maen Arthur,
one of the wildeft and moft romantic fpots in Wales. It is
always found on a micaceous or quartzofe ftone.