Delesseria.] ALGJE RHODOSPERME^E. 191 



lular 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 substance 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. jP. sang. E. Bot. t. 1041. 



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

 Stem elongated, bearing- leaves 6 8 inches long and 1 5 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. Hook. Br. Fl. v. ii. p. 285. E. Bot. t. 1387. /3. an- 

 gustissima, Turn. Frond extremely narrow, without any trace 

 of lateral membrane. Turn. t. 160. 



On the larger Algae, 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, 



