P la t e LXXXIII.
DELESSERIA ANGUSTISSIMA, Griff. MSS.
Gen . C h a r . Frond rose-red, flat, membranaceous,'*' witb a percurrent midrib.
Fructification of two kinds, on distinct individuals; 1, spberioal
tubercles [coccidia) immersed in the frond, and containing a globular
mass of angular spores; 3, tetraspores forming defined spots in the
frond, or in leaf-like processes. D elesseria [Ag),-—in honour of
Baron Benj. Belessert, a distinguished botanist and patron of botany.
D elesseria angustissima; frond membranaoeo-cartilaginous, compressed,
very narrow, two-edged, much branched; branches alternate, distichous
of unequal length, much divided above, and furnished with
numerous forked ramuli; tubercles imbedded either in the tips of the
frond, or in small axiUary ramuli; tetraspores forming sori (on distinct
plants) either in the inflated apices, or in axillary, lanceolate
ramuli.
Delesseria alata, y. angustissima, Ag. Sp. Alg. vol. i. p. 179. Ag. Sgst.
p. 350. Grev. Alg. Brit. p. 74. Hook. Br. M . vol. ii. p. 386.
D e l e s s e r ia a la ta , /3. an g u s tifo lia , Lyngb. Hyd. Ban. p . 8. (?)
B hodomenia rostrata, J. Ag. MSS.
G ig a r t in a p u rpm-a scen s, y. ro s tr a ta , Lyngb. Hyd. Ban. p . 4 6 . 1 . 1 2 . fide J.
Ag. ( b u t tlie fig u re is n o t c h a ra c te r is tic ) .
G e l id iu m ? ro s tr a tiu n . Griff, in Harv. Man. p . 8 2 .
F u cu s alatus, y. angustissimus. Turn. Syn. Fuc. vol. i. p. 145. Turn. Hist.
1 .160. fig. k -l.
F u cu s alatus, junior, Gm. Hist. t. 25. f. 2.
H a b . Parasitical on the stems of Laminaria digitata, often accompanying
Bel. alata. Perennial. Winter and Spring. Scarborough, Mr.
Pitehford. Lossiemouth, Morayshire, Mr. Brodie. Aberdeen, Br.
Bickie. Orkney, Rev. J. H. Pollexfen. Galway, Mr. Reilly. Cornwall,
Mr. Ralfs. Kingstown, Mr. Andrews.
Geoge. D is t e . Arctic Sea, and Northern Atlantic Ocean. Greenland. Norway?
Desce. Root, a small disc. Fronds tufted, 4 -8 inches long, nearly cylindrical
below, compressed and two-edged above, not half a line in diameter,
becoming graduaUy more slender towards the tips, much and irreg-ularly
branched. Branches distichous, irregular, alternate or subdichotomous,
frequently bare of ramuli in their lower p a r t; above more or less amply
fm-nished with patent, once or twice forked, ramuli from a quarter to half
an inch in length. Apices acute. Colour a very dark red. Substance cartilaginous,
rather flaccid. Fructification; 1, tubercles mostly immersed in
small accessory ramuli, springing from the axils of the upper branches,
spherical, containing a moderately dense mass of spores, sometimes immersed
in the apices of the frond. 2, tetraspores contained in the inflated tips
of the branches, or in smaU, simple or forked, spindle-formed, accessory
ramuli, seated in the axils of the upper branches.
* In this species the is obsolete, the frond consisting altogether, or
Y