Delesseria.] AhOM RHODOSPERME^. 191 



hilar texture ; cellules often highly developed. Frond flat, foli- 

 aceous, compressed or cylindrical, occasionally filiform or fila- 

 mentous, inarticulate. Fructification mostly double, and pro- 

 duced on distinct individuals of the same species. 1. Capsules, 

 or tubercles, containing a mass of ovate or pear-shaped red seeds: 

 2. granules, scattered or collected into little groups, and situated 

 either in the substa?ice of the frond or in distinct processes. 



36. Delesseria. Lamour. Delesseria. 



Frond rose-red, flat, membranaceous, with a percurrent midrib, 

 Fruct. of two kinds. Capsules containing a globular mass of 

 seeds and ternate granules, forming definite sori in the frond 

 or in distinct foliaceous leaflets. Grev. — This beautiful 

 genus, distinguished from every other in the tribe by its per- 

 current midrib, is inscribed to M. Benjamin Delessert, a dis- 

 tinguished French naturalist and patron of Botany. 



1. D. sanguinea, Lamour. Oak-leaved Delesseria. Stem 

 cylindrical, branched, bearing oblong, waved, transversely 

 veined, entire leaves ; midrib percurrent, strong. Hook. Br. 

 Fl. v. ii. p. 285.— F. sang. E. Bot. t. 1041. 



Sea-shores, frequent ; particularly large at Larne ; Dr. Drummond. 

 Stern, elongated, bearing leaves 6 — 8 inches long and 1 — h broad, deli- 

 cate, waved and plaited, the margin quite entire. Fructification is 

 only borne on the battered fronds in winter and spring. Miss Ball finds 

 a curious variety at Youghal, in which small leaflets spring from the 

 midrib of the larger ones, something in the manner of Del. Hypoglossum. 



2. D. sinuosa, Lamour. Sinuous-leaved Delesseria. Stem 

 elongated, branched, beset with oblong or obovate, dentato- 

 sinuate or pinnatifid, transversely ribbed leaves. Hook. Br. Fl. 

 v. ii. p. 285. — Fucus sinuosus. E. Bot. t. 822. 



On the larger Fuci, very common ; very fine at Larne ; Dr. Drum- 

 mond. Fronds 6 — 8 inches long or more, of a darker and duller 

 colour than the preceding ; the transverse veins much stronger. 



3. D. alata, Lamour. Winged Delesseria. Stem excessively 

 branched, somewhat dichotomous, winged with membrane, 

 without distinct leaves; branches linear, attenuate; margin 

 entire. Book. Br. Fl. v. ii. p. 285. E. Bot. t. 1387.— j3. an- 

 gustissima, Turn. Frond extremely narrow, without any trace 

 of lateral membrane. Turn. t. 160. 



On the larger Alga?, very abundant. 4 — 8 inches high ; deep red, 

 excessively branched, very variable in the relative breadth of the mem- 

 brane. Dr. Turner's var. 3. is a very curious state of this plant, and 

 has not yet (that I am aware) been found in Ireland. 



4. D. Hypoglossum, Ag. Proliferous Delesseria. Frond 

 (originally) linear-lanceolate, excessively branched ina proli- 

 ferous manner ; innovations lanceolate, attenuated and acute, 



