Ser. RHopOsPERME”. Fam. Rhodomelee. 
Prats CII. /. 
POLYSIPHONIA OBSCURA, J. 4%. 
Gon. Cuan. Frond filamentous, partially or generally articulate ; joints lon- 
gitudinally striate, composed of numerous radiating cells or tubes 
disposed round a central cavity. Fructification two-fold, on different 
individuals ; 1, ovate capsules (ceramidia), furnished with a terminal 
pore, and containing a mass of pear-shaped spores. 2, ¢etraspores 
imbedded in swollen branchlets. PotystpHonta (Grev.), from modds, 
many, wd ciper, a tube. 
PoLystPHoNtA obscura; densely matted together, filaments creeping, throw- 
ing up erect, simple, secund branches, which are either naked or fur- 
nished with a few secund ramuli; articulations as long as broad, many- 
tubed. 
PotysiPHoNtA obscura, J. 4g. Alg. Medit. p.123. Endl. 3rd Suppl. p. 44. 
Hurcuinsta obscura, 4g. Sp. vol. ii. p. 108. 
ConFeERvVA intertexta, Roth, Cat. Bot. vol.i. p. 188. t. 3. f. 5. vol. il. p. 214. 
Has. Spreading over marine rocks, at half-tide level; also parasitical on 
Fuci, and on some of the smaller Alge. Jersey, Juss White. On 
the sheltered side of a lofty rock, near Sidmouth, Rev. Mr. Cresswell. 
Groer. Distr. Coast of Spain, at Cadiz, dy. Adriatic Sea. 
Descr. Plant spreading over the surface of rocks, in patches of six inches to a 
foot in diameter, covering the roots of such uci as it may encounter. Fila- 
ments decumbent, attached by means of rooting processes, which issue at 
intervals from the lower surface, subsimple, throwing up from the upper 
surface erect, secund branches, from a quarter to half an inch in length, 
quite simple, and tapering to a fine point, naked, or furnished with three 
or four secund simple ramuli. 4rticudations visible in all parts of the frond, 
about as long as broad, or rather shorter, composed of twelve or thirteen 
radiating tubes. The fruit I have not seen on British specimens. Colour, 
dark brown-red. Swéstance rigid, imperfectly adhering to paper. 
This interesting addition to the British Flora, was made by 
Miss White, who detected, in 1846, a single specimen growing 
among the roots of P. fibrata, at Jersey. More recently it has 
been gathered in great abundance by the Rev. Mr. Cresswell, in 
a station near Sidmouth, and to his kindness I am indebted for 
numerous specimens, gathered at various seasons. 
I had, at first, confounded it with P. secwnda, Mont., a plant 
to which, outwardly, it bears a strong resemblance, but from 
which it differs in the length, and composition of the articulations. 
IT have now minutely compared the British specimens with 
one of P. obscura, received from Prof. J. Agardh, and find them 
to agree in all essential particulars; owrs are, however, rather 
more robust than the Adriatic plant, and the joints slightly 
shorter. 
