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Conf. atrovirens Dilhv. t. 25. Lichen pubescens, E. Bot.
t. 2318.; Harv. in Hook. Br. Fl. ii. p. 363. St. atrovirens
Harv. in Manual, p. 153.
Ilab. On wet rocks forming the banks to the river
Diloris, near Neath, Glamorganshire: Mr. Dillwyn.
Mountainous d istric t; 14 miles west of Aberdeen: Dr.
Dickie. On wet rocks above the falls of Aherdylais,
Swansea: Gutch.
This species forms rigid lustreless and very dark tu f ts ;
the filaments are divaricately branched, the branches narrower
than the stem, and sometimes furnished with two or
three secondary ramuli. The larger divisions are dark brown
and opaque, the smaller vivid green, their terminations being
marked with transverse lines, which indicate the divisions into
cells. The dense cartilaginous sheath is most visible at the
terminations of the branches.
2. Stigonema mamillosum Ay.
Plate L X V I . Figs. 2, 3.
Char. Branches incrassated, spindle-shaped, the two inferior
thirds densely mamillose on all sides.
Banqia mamillosa Lyng. t. 25. ; Harv. in Hook. Br. Fl.
p. ii. p. 363. Stig. mamillosum Harv. in Manual,
p. 153.
JIah. Rocky bottoms of subalpine rivulets, Appin : Capt.
Carmichael. Eagle’s nest, Killarney : W. H. Harvey.
Mountainous d is tric t; 14 miles west of Aberdeen;
Dr. Dickie.
This forms continuous tufts several inches in diameter,
Avhioh are less rigid than in S. atrovirens; the branches are
simple, their diameter being greatest in the middle, and beset
on all sides, for the two loAver threads with mamilG of
various sizes, and the cells of which are always cylindrical,
and not moniliform. These mamillae as well as the npper
third of the branches are frequently of a vivid green colour.
I t IS ju s t probable tha t this species is but a condition of the
previous one, the differences observed being occasioned by its
moister habitat.
3. Stigonema pannieokme Harv.
Plate L X V I . Figs. 4, 5.
Char. Fdaments dark broion, densely packed together, much
branched. Branches long, flexuous, obtuse. Cells angular,
in triple series.
Scytonema panniforme Carm. MS. ; Ag. Syst. p. 309 ?
Stigonema panniforme Harv. in Manual, p. 154.
Hab. On rocks at the mouth of Spar Cave : Capt. Carmichael.
“ Patches indeterminate, crust-like, velvety. Filaments so
closely packed that only their tops are visible above the crust,
very tough when dry, gelatinous Avhen moist, cohering
strongly together, much branched ; branches long and fiexuou^
divaricating, cylindrical, quite obtuse, not tapered. Granules
ternate, very^ obvious in all the main branches, less distinct
towards the tips. This entirely agrees In external character
and ramification with the Scytonema panniforme of Agardh,
with an authentic specimen of which I have compared Carmichael’s
specimen. The only difference I can perceive lies in
the generic character, and this I suspect depends on age, for
I find the apices of the branches simply striated, like a Calothrix
or Scytonema, and the smaller branches, for, at least,
part of their length, have the semi-punctate appearance of S.
ocellatum ; and it is only in their larger and main branches
th a t the punctated character is clearly visible.” Harv.
4. S tigonema interruptum Hass.
Plate L X IX . Fig. 2.
Char. Filaments thick, subulate, coriaceous, glaucous green,
Q 3