Conferva distorta, Dill. Conf., t. 2 2 ,/. A. E
Calothrix distorta, Harv. Man. 158. Mack. Hib. 237.
Elisa distorta, Gray. Arr. i., 282.
In ponds and lakes.
Plate CIX. fig. 3. Portions of Trichomes x 400.
T o lyp o th z ix cizzhosa. {Carm.)
Floating cæspitose, olive, or blue-green, becoming brownish ;
trichomes nearly simple, rather stout, distinctly articulate,
pallid blue-green, joints finely granular, one-half or one-third
as long as broad ; sheaths moderately narrow (rath e r broad in
some of the older trichomes), indistinctly lamellose, smooth ;
heterooysts scattered.
S iz e . Trichomes -012--014 mm., with sheath -02--025 mm.
Scytonema cirrhosum, Carm. Eng. Fl. v., 366. Harv. Man.,
155 (not of Eng. Bot. ii., t. 2920).
Arthronema cirrhosum, Hass. Alg. 238, t. 6 8 , f. 7. Rabh.
Alg. Eur. ii., 267.
In mountain lakes.
“ I t forms flexaous tufts of brown, very slender threads, proceeding in
fascicles from membranous sub-erect sheaths, aud containing a single
row of cells scarcely so long as broad.”— Carm.
Plate CVIII. fig. 3. Portions of trichomes X 4iOO; a, hormogone
X 400.
A P P E N D IX .
Although included by Thnret and Bornet, and also by
Kirchner, with Algæ, it can scarcely be doubted that all the
members of the genera Stigonema (or Sirosiphon) and PLapalo-
siphon must be transferred to the Lichens. Tliey are included
here in the form of an appendix, for the satisfaction of students,
who wonld naturally expect some reference to them in a w'ork
of this kind. At the same time we have availed ourselves of
the opportunity to add figures, and descriptions, of two or three
uncertain species, which have been recorded as British, under
new and unknown genera.
Genus 111. STIGONEMA. Ag. (1824.)
Cells of th e trichome often geminate or ternate, in conséquence
of their lateral multiplication, or even forming tran sverse,
several-oelled bands. Sheath large. Cells surrounded
with a thick membrane, very prominent in the old filaments.
Hormogones originating in lateral branchlets formed of a single
row of cells.
s tig o n em a o c e lla tum . Thur. Ann. Sci. Nat. 1875, i., 377.
More or less expanded, woolly-tomentose, dark olive brown,
cells of the trichome for the most pa rt biseriate, sub-globose,
or oblong-compressed, equal or one-third as long as broad,
filled with a granular blue green plasma; slieaths very thick,
lamellose, dark golden brown, external stratum now and then
paler, cells of the branches for the most part uniseriate, ocellate,
sometimes much elongated, apex obtuse, rounded, seldom again
branched, sheaths colourless or yellowish, quite smooth.
S iz e . W ith sheath about '04 mm. Cells -01-'012 mm.
Kiroh. Alg. Schl. 230.
Sirosiphon ocellatus, Kutz. Tab. Phyc. ii., t. 37, f. 2. Rabh.
Alg. Eur. ii., 286.
Hassallia ocellata, Hass. Alg. t. 67, f. 2, 7, 6. Fischer
Nost., fig. 1 1 .
Conferva ocellata, Dillw. Conf. t. D. Eng. Bot. i., t. 2530.
Scytonema ocellatum, Harv. Eng. Fl. v., 364. Harv. Man.
164. Grev. Fl. Ed. 302. Gray, Arr. i., 285. Eng. Bot. ii.,
t. 2514.
On inundated ground, in swamps and moors.
Plate ex. fig. 2. Portion of extremity of trichome X 400.
S tig on em a B o u t e illii. {Breb. Ann. Sci. Nat.)
Tufts small, immersed, cushion-like and rounded, dark brown,
trichomes very short, variously curved and contorted, olive, or
golden brown, sparsely branched, sometimes simple, internally
sometimes interrupted, formed from one series of cells one-third
or one-fourth as long as broad, branches unilateral, very short,
arched, sheaths narrow, colourless or very pale yellow, hyaline
and even, or with the outer stratum falling away in fibrils.
S iz e . Trichome •04--06 mm. Cells '01, with envelope -02
mm.
Sirosiphon Bouteillii, Breb. & Desm. in Ann. Sci. Nat. ser.
4, V o l.iv ., p. 2.
On calcareous rocks and chalky cliffs.
Plate e x . fig. 3. Portion of trichomes X 400.
S tig on em a p annifozme. Kirch. Alg. SclA. 230.
Forming a thin tomentose stratum, more or less expanded,
dark brown, trichomes ascending, very much branched, variously
curved, branches unilateral, here and there fasciculate, often abbreviated,
rounded at the apex, internal cells pale bine green,
granulose, globose then compressed, arranged in a single, rarely