2920.
SCYTONEMA eirrhosum.
Tufted Scylonema.
CRYPTOGAM1A Alga.
Gen. Char. Filaments branched from the rupture
of their sheath and the division of the projecting
thread. Endochrome brown or olivaceous,, transversely
striated, at length separating at the striae
into lenticular seeds.
Spec. Char. Tufts widely spreading. Filaments
floating in bundles, extremely slender, highly
flexuous.
Syn. Scytonema eirrhosum. Carm. MSS. Eng.
FI. v. 5.pt. \.p . 366. Harv. Man.p. 155.
Arthronema eirrhosum. Hass.p. 238. t. 68.ƒ. 7.
T WO very different’modes of ramification occur in the
Algae hitherto associated under the genus Scytonema, as
exhibited by S. ocellatum and S. myochrous. In the former
the branch springs immediately from one of the rings, and is
at right angles to the thread; in the latter the sheath bursts,
and the contained thread issues from the aperture, forming at
length two distinct branches, each of which increases independently,
and, again giving rise to new branches, increases
the plant. Taking the latter as the type of the genus Scytonema,
though both are referred as varieties to the same species
by Agardh, I had purposed to propose for those species
which resemble S. ocellatum in structure the name of Has-
sallia, but before I had an opportunity of publishing it, Kiitzing
gave to one of the species the name of Sirosiphon, which,
according to the received botanical canon, must be retained.