ny 9 "72, 
Ser. RHODOSPERME”. Fam. Delesserrea. 
Prats LX XXIII. 
DELESSERIA ANGUSTISSIMA, Grif. SS. 
Gen. Cuar. Frond rose-red, flat, membranaceous,* with a percurrent mid- 
rib. Fructification of two kinds, on distinct individuals ; 1, spherical 
tubercles (coccidia) immersed in the frond, and containing a globular 
mass of angular spores; 2, ¢e¢raspores forming defined spots in the 
frond, or in leaf-like processes. DELEssSERIA (Ag.),—in honour of 
Baron Benj. Delessert, a distinguished botanist and patron of botany. 
De esserta angustissima; frond membranaceo-cartilaginous, compressed, 
very narrow, two-edged, much branched; branches alternate, disti- 
chous of unequal length, much divided above, and furnished with 
numerous forked ramuli; tubercles imbedded either in the tips of the 
frond, or in small axillary ramuli; tetraspores forming sori (on dis- 
tinct plants) either in the inflated apices, or in axillary, lanceolate 
ramuli. 
Devesserta alata, y. angustissima, 4g. Sp. Aly. vol. i. p. 179. Ag. Syst. 
p. 250. Grev. Alg. Brit. p.'14. Hook. Br. Fl. vol. ii. p. 286. 
Devesserta alata, 8. angustifolia, Zyngb. Hyd. Dan. p. 8. (°) 
RHopoMENIA rostrata, J. 4g. MSS. 
GIGARTINA purpurascens, y. rostrata, Lyngb. Hyd. Dan. p. 46. t. 12. fide J. 
4g. (but the figure is not characteristic). 
GELIDIUM? rostratum, Griff. in Harv. Man. p. 82. 
Fucus alatus, y. angustissimus, Turn. Syn. Fue. vol. i. p. 145. Turn. Hist. 
t. 160. fig. A-0. 
Fucus alatus, junior, Gm. Hist. t. 25. f. 2. 
Has. Parasitical on the stems of Laminaria digitata, often accompanying 
Del. alata. Perennial. Winter and Spring. Scarborough, Wr. 
Pitchford. Lossiemouth, Morayshire, Mr. Brodie. Aberdeen, Dr. 
Dickie. Orkney, Rev. J. H. Pollexfen. Galway, Mr. Reilly. Corn- 
wall, Mr. Ra/fs. Kingstown, Mr. Andrews. 
Gnoer. Distr. Arctic Sea, and Northern Atlantic Ocean. Greenland. Norway ? 
Descr. Root, a small disc. Fronds tufted, 4-8 inches long, nearly cylin- 
drical below, compressed and two-edged above, not half a line in diameter, 
becoming gradually more slender towards the tips, much and irregularly 
branched. Branches distichous, irregular, alternate or. subdichotomous, 
frequently bare of ramuli in their lower part; above more or less amply 
furnished with patent, once or twice forked, ramuli from a quarter to half 
an inch in length. -Apices acute. Colour a very dark red. Substance car- 
tilaginous, 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, ¢efraspores contained in the inflated tips 
of the branches, or in small, simple or forked, spindle-formed, accessory 
ramuli, seated in the axils of the upper branches. 
* In this species the membrane is obsolete, the frond consisting altogether, or 
very nearly, of midrib. 
Xs 
