114 DELESSERIA. 



containing a tuft of filaments, bearing the spores : 2, tetra- 

 spores forming definite spots in the frond, or in distinct leaf- 

 like processes. Named in honour of M. Benj. Delessert, a 

 distinguished French naturalist and patron of Botany. 



1. D. sanguinea, Linn. ; stem cylindrical, cartilaginous, 

 branched, bearing oblong or obovate, transversely veined 

 leaves, entire at the margin ; midrib percurrent, strong ; tu- 

 bercles stalked, attached to the midrib. Grev. Alg. Brit. p. 

 72 ; Hook. Br. Fl. ii. p. 285 ; Wyatt, Alg. Danm. No. 13 ; 

 Harv. Phyc. Brit. t. cli. Fucus sanguineus, E. Bot. t. 1041. 



In the sea. Biennial. Fruiting in winter, after the decay of the leaves. 

 Common. Stem simple or slightly branched, thick, bearing numerous ob- 

 long or broadly obovate, obtuse, penninerved leaves, 2 8 inches long, 1 6 

 inches wide, of a splendid pinky-red colour and delicately membranous 

 substance ; the margin waved, but quite entire ; the midrib and lateral 

 veins prominent, the former occasionally giving rise to small proliferous 

 leaves. Such is the summer state. In winter the membranaceous portion 

 of the frond almost entirely decays, leaving little but the stems and mid- 

 ribs, which are then found fringed with fructification ; the tubercles raised 

 on little stalks about a line long; the tetraspores placed in little leafy pro- 



2. D. sinuosa, Good. & Wood.; stem elongated, branched, 

 beset with oblong or obovate, deeply sinuate or pinnatifid, 

 toothed, penninerved leaves; nerves opposite. Hook. Br. 

 Fl. ii. p. 285 ; Wyatt, Alg. Danm. No. 62 ; Harv. Phyc. 

 Brit. t. cclix. Fucus sinuosus, E. Bot. t. 822. 



On the larger Fuci, common. Biennial ? Summer and autumn. Stem 

 in young plants with a decurrent membrane (the remains of the simple leaf 

 of which the plant at first consists) ; in old, naked and somewhat pinnat- 

 edly branched ; the branches or leaves of an oblong or obovate form, deeply 

 sinuate, or in many specimens pinnatifid, each lobe having a sinuous, jag- 

 ged or serrated, sometimes ciliated margin ; furnished with a strong mid- 

 rib, and transverse opposite veins. Colour a fine rose-red, purplish when 

 dry; much duller at all times than that of the preceding. Fructification : 

 ] , tubercles imbedded in the midrib of the leafy lobes -. 2, tetraspores placed 

 in minute, slender processes, fringing the margin, and resembling cilia, 

 formed out of a dissolved portion of the midrib. 



3. D. alata, Huds. ; stem excessively branched, some- 

 what dichotomous, linear, winged with membrane without 

 distinct leaves ; branches attenuate ; margin entire. Grev. 

 Alg. Brit. p. 73 ; Hook. Br. Fl. ii. p. 285 ; Wyatt, Alg. 

 Danm. No. 14; Harv. Phyc. Brit. t. ccxlvii. Fucus alatus, 

 E. Bot. t. 1387. 



On the larger Algae, common. Biennial? Summer. Frond 3 8 

 inches high, 1 4 lines wide, much branched in a dichotomous manner, 

 linear, the membrane decurrent along the branches, its margin quite entire, 



