Ser. RHODOSPERMEX. Fam. Delesseriea. 
Puate XXVI. 
DELESSERIA RUSCIFOLIA, Zamour. 
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, ¢efraspores forming defined spots in the 
frond, or in leaf-like processes. Dutusser1a—in honour of Baron 
Benj. Delessert, a distinguished Botanist and Patron of Botany. 
Detesserta ruscifolia; frond linear-oblong, obtuse, repeatedly proliferous 
from the mid-rib with leaflets of a similar form ; leaflets traversed by 
oblique, anastomosing, pellucid striz ; tubercles on the mid-ribs of the 
smaller leaflets; tetraspores forming linear spots at each side of the 
mid-rib. 
De esserta ruscifolia, Lamour. Ess. p. 124. Ag. Sp. Alg. vol.i. p.175. Ag. 
Syst. p. 249. Grev. Alg. Brit. p.76. Hook. Br. Fl. vol.ii. p. 286. Hare. 
in Mack. Fl. Hib. part 3. p. 192. Harv. Man. p.56. Endl. 3rd Suppl. p. 53. 
Me’ Calla, Alg. Hib. no. 12. 
WormskIozpia ruscifolia, Spreng. Syst. Veg. vol. iv. p. 331. 
Hypoatossvum ruscifolium, Kitz. Phye. Gen. p. 444. 
Fucus ruscifolius, Turn. in Linn. Trans. vol. vi. p.127. t. 8. f.1. Syn. Fue. 
p-ll. Hist. t.15. Sim. Eng. Bot. t.1395. 
Has. Generally growing on rocks, near low water mark ; sometimes para- 
sitical on other Alge. Annual. Spring, Summer, and Autumn. 
Not uncommon on the shores of England and Ireland. 
Grocer. Distr. Atlantic shores of Europe. Cape of Good Hope, W. H. H. 
Van Dieman’s Land, Mr. Gunn. 
Desc. Root asmalldise. Fronds several from the same base, consisting of a 
primary leaf 2—4 inches in length, about 4 lines in breadth, linear-oblong, 
obtuse, undivided, entire at the margin, but often somewhat wavy and curled, 
with a strong mid-rib, producing numerous other leaves in a proliferous 
manner, all of similar shape to the primary ; and these again producing a 
third and fourth set, until there results a much branched frond. All the 
leaflets spring regularly from the mid-ribs of those first formed. The cel- 
lules composing the membrane of the leaves are very minute, angular and 
closely packed; but the substance is traversed with branching and anasto- 
mosing, pellucid, jointed striz or veinlets, composed of a single string of 
elongated cellules, and running in an oblique direction, from the mid-rib to 
the margin. Zwdercles seated on the mid-ribs, generally toward the apices 
of the younger leaves. Sori linear, elongated, forming interrupted lines at 
each side of the mid-rib. Colour, a transparent blood-red. Swéstance more 
rigid than in D. Hypoglossum. 
Delesseria ruscifolia was discovered on the Yarmouth shore by 
