ru/F c ijx x v iir .
W.H-H a*l eb htK. Kecvi'.V.onham iHîeevc.iiug
P l a t e CLXXXVIII.
CALLITHAMNION TETRICUM; A g .
G e n . C h a r . Frond rosy or b row n ish red , filamentous ; stem e ith e r opake
an d c ellular, o r tr a n s lu c e n t a n d jo in te d ; b ran ch es jo in te d , o n e-tubed,
mostly p in n a te (rarely d ichotomous or irreg u la r) ; dissepiments hyaline.
F ru it of two k in d s , o n d is tin c t p la n ts ; 1, ex te rn a l te tra sp o re s, s c a tte
re d a lo n g th e u ltim a te b ra n c h le ts, or b o rn e on little pedicels ; 2,
ro u n d ish or lobed, b e rry -lik e receptacles ( f aveller) seated on th e ma in
b ran ch es, a n d c o n ta in in g n um e ro u s , an g u la r spores. C a l l i t h a m n i o n
(Ly n g h ), from koXos, beautiful, a n d Sagmov, a little shrub.
C a l l i t h a m n i o n tetricum-, rig id , s h ru b b y ; stem an d b ra n d ie s ro b u s t,
densely covered w ith ram n li, shaggy below, p lum u la te ab o v e ; p lu mule
s crowded, qu ad rifa rio u s, simply p in n a te ; p in næ acute, ta p e rin g
to th e base, e re c to -p a ten t ; a rtic u la tio n s twice or tlirice as long as
b ro ad ; te tra sp o re s elliptical, m in u te , sessile on s h o rt la te ra l processes
o f th e pin næ .
Callithamnion tetricum, Ag. Sp. Alg. vol. ii. p. 179. Harv. in Hook. Br.
FL vol. ii. p. 342. Harv. in Mack. Fl. Hib. p a rt 3. p. 214. Harv. Man.
p. 108. Wyatt, Alg. Banm. no. 141. Endl. 3rd Suppl. p. 34.
F iilebothamnion tetricum, Kiitz. Phyc. Oen. p. 374.
Conferva tétrica, Billw. t. 81. F. Bot. t. 1915.
I Ia b . On the perpendicular faces of rocks within tide marks, from half-tide
level to low-water mark. Perennial. Summer. Common on the
shores of the south of England and south and west of Ireland ; less
frequent on the east coast. Lambay, Mr. Me’ Calla. Channel Islands.
Geogr. Dis t r . Northern coasts of France, common.
De sc r . Boot, a large disc, densely covered with interwoven fibres. Fronds two to
eight inches long, or more, tufted, fruticose ; stems as tliick, or twice as thick
as pack-thread, much branched, the branches long, and either simple or again
divided, alternate, spreading on aU sides, and densely clothed with shaggy
or hair-like, coarse, irregularly divided ramuli, so that the divisions of the
frond have the appearance of rough ropes ; upper and younger divisions
clothed with longer and more slender branchlets, which bear alternate
spreading plumules : similar plumules spring from all parts of the shaggy
branches, growing among the irregular ramuli. Plumules long and
narrow, simply pinnate, straight ; pinnæ erecto-patent, tapering to an acute
point, and much narrowed at base. Arliadations about twice as long as
broad, somewhat constricted at the dissepiments. Tetraspores two or three
together, eUiptical, minute, sessile on the inner faces of short ramuli, which
issue from the sides of the pinnæ. Favellæ binate, borne on the pinnæ
(frequently shortened) of less regular plumules. Colour a very dark, dull,
brownish red. Substance rigid, not very closely adhering lo paper, soon
decaying iu fresh water after the plant has been once dried, and then exhaling
the odour of violets,
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