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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 87
RALFSIA, Berkeley.
(In honor of John Ralfs, an English botanist.)
Fronds olive-brown, forming flat coriaceous or crustaceous expansions of indefinite
extent, composed of a single horizontal layer, from which arise short vertical
filaments, which are firmly united to one another so as to form a solid
parenchymatous structure; fruit scattered over the surface of the fronds in spots
(sori), which are composed of club-shaped, several-celled paraphyses, at whose base
are borne the unilocular sporangia; hairs arising from crypts in the frond;
plurilocular sporangia unknown; growth peripheral.
A genus containing only about half a dozen species. In its mode of growth the frond resembles that of
Myrionema, but the vertical filaments are not free, as in that genus, but united so as to form a solid
mass. R. verrucosa, the typical species, has a well-developed frond, but in R. clavata the frond is minute
and the fruit-dots are usually confluent, so that the species has by some been placed in Myrionema.
R. VERRUCOSA, Aresch. (R. deusta, Berk.; Phyc. Brit, Pl. 98.) Fronds licheniform,
adherent throughout, crustaceous or membranaceous, at first orbicular, at length
becoming indefinite in outline, one to six inches in diameter, zoned and irregularly
tuberculated, the newer lobes overlapping the older; sori scattered; paraphyses .06-
12 mm long, clavate, few-celled; unilocular sporangia ovoid or pyriform, .038 mm long by
.019 mm broad.
Common on rocks in pools at half-tide from Nahant northward; Europe.
A homely, dark-colored species, which has more the habit of a lichen than an alga. It abounds on the
northern coast in shallow exposed pools, and is found at all seasons. At first the crusts are of small size
and adhere closely to the rocks, but afterwards, as they increase in size, they become lobulated and
rough and are easily detached. The species, contrary to the statement of Janczewski, is furnished with
tufts of hairs at certain seasons of the year. It may occur also south of Cape Cod, but, if so, it must be in
a reduced form.
R. DEUSTA, J. Ag.
Fronds licheniform, membranaceous, attached at center, margin free, irregularly
orbicular, with overlapping marginal lobes, marked with concentric zones and with
radiating striæ; spores?
At low water mark.
Eastport, Maine.
A larger and more foliaceous species than the preceding, being about .25-30 mm in thickness. Both the
concentric zones and radiating striæ are well marked, and the species is comparatively loosely attached
to the substratum. On sectioning the fronds of R. deusta, the cells are seen to be arranged in lines
which curved upwards and down wards from a medial plane, while a section of the frond of R. verrucosa
shows the cells arranged in lines which curve upwards from the attached base.