Ser. M e la n o s p e rm e æ . Fam. Ectocarpeoe.
P l a t e CCCXLIX.
SPHACELARIA RACEMOSA, Grev.
Gen. C h a r . Filaments jointed, rigid, distiohously branched, pinnated;
rarely simple or subdichotomous. Apices of the branches distended,
membranous, containing a dark, granular mass. Fructijication, elhp-
tical utricles (or spores), borne on the ramuli. S p h a c b l a r i a (Lyngb.),
—from cr</>aKeXos, gangrene, alluding to the withered tips of the
branches.
S p h a o e l a r i a racemosa ; “ an inch in height, tufted, olivaceous, somewhat
rigid, the fronds dichotomous; articulations equal in length and
breadth; capsules oval, racemose, pedunculate.” Grev.
Sphaoelaria racemosa, Grev. Soot. Orypt. FI. vol. ii. t. 96. Grev. FI. Edin.
p. 814. Harv. in Hook. Br. FI. vol. ii. p. 325. Harv. Man. ed. 1. p. 39.
ed. 2 .p . 57. J .A g . S p . A l g . Kütz. Sp. A lg .-ÿ. 133.
H a b . In tide-pools? Very rare. Frith of Forth, opposite to Caroline
Park, S ir John Eichardson.
Geogr. D is t r . Only found in the above locality, and there only once (about the
year 1821).
D esc r. “ Plant tufted, about an incli in height, of an olive-green or olive-brown
colour. Frond filiform, somewhat rigid, 3-4 times dichotomous, the dichotomies
acute. Articulations equal in length and breadth, diaphanous to the
base. Sanvmits of the branches not sphacelated in my specimens, but
somewhat dilated and hyaline, as in many other species previous to the sphacelation
making its appearance. Fructijication, oval capsules, surrounded
by a very narrow pellucid border, pedicellate, and airanged in a racemose
manner, on a common jointed peduncle. Racemes suberect, arising from
various parts of the frond,”-—Grev. Scot. Orypt. I. c.
In this species we have the remarkable fact, occasionally met
with in all departments of natural history, of a species distinguished
by strongly marked characters having been seen but once,
and that in very small quantity. The tuft from which Dr. Greville’s
figure, and the above description, which I have transferred
from his work, were taken, has also served me in making the
drawing for the plate now given, having been kindly placed m
my hands for that pm’pose by Dr. Greville, with the liberal per-
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