PDF file (text) - Cryptogamic Botany Company

REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 63
SCYTOSIPHON, (Ag.) Thuret.
(From σκυτος [skytos], a whip, and σιφων [siphon], a tube.)
Fronds simple, cylindrical, usually constricted at intervals, hollow, cortex of small
colored cells, inner layer of vertically elongated, colorless cells; sporangia as in
Phyllitis; paraphyses single-celled, oblong-obovate, interspersed among the
sporangia.
The present genus is founded on the Chorda lomentaria of older writers. The genus Scytosiphon, as
proposed by Agardh, included both C. lomentaria and C. filum. The latter species, which is still kept in
the genus Chorda by most writers, has the surface of the frond covered with club-shaped paraphyses,
between which are situated the oval unilocular sporangia. In S. lomentarius the bodies called
paraphyses are only occasionally found, and their real nature is a little uncertain. Both Bornet and
Areschoug consider them to be paraphyses, and the latter has figured them in Observationes
Phycologicæ, Part III, Pl. 2, Fig. 1. As at present understood, Scytosiphon differs from Phyllitis only in
the fact that the frond is tubular instead of membranous, and in the presence of paraphyses, which
have not yet been found in Phyllitis.
S. LOMENTARIUS, Ag. (Chorda lomentaria, Lyngb.; Phyc. Brit., Pl. 285.—Chorda
filum var. lomentaria, Kütz., Spec. Alg.)
Fronds gregarious, three to eighteen inches long, attached by a disk-like base,
shortly stipitate, expanding into a hollow tube, from a quarter of an inch to an inch
in diameter, at first cylindrical, afterwards constricted at intervals.
Very common on stones between tide-marks; found nearly all over the world.
A species easily recognized, except when quite young, by its tubular and constricted frond, but chiefly
interesting in consequence of the smaller species of algæ which grow upon it. At Eastport a very large
form is found, nearly an inch in diameter, and much twisted.
FAMILY PUNCTARIEÆ.
Fronds unbranching, forming expanded membranes or cylinders; fructification in
spots (sori) on the surface of the fronds; plurilocular sporangia ellipsoidal, composed
of few cells; unilocular sporangia spheroidal.
PUNCTARIA, Grev.
(From punctum, a point, referring to the dots formed by the sporangia and hairs.)
Fronds olive-brown, simple, membranaceous, attached by a discoidal base, composed
of several (2-6) layers of cuboidal cells of about the same dimensions in all parts of
the fronds; unilocular sporangia immersed in the frond, collected in spots, sphericalcuboid,
formed from the superficial cells; plurilocular sporangia collected in spots,
immersed except