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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 61
SUBORDER PHÆOSPOREÆ.
Reproduction by means of olive-brown zoospores which have two laterally attached
cilia; sporangia of two kinds—unilocular, containing a large number of zoospores,
and plurilocular, compound sporangia, each cell of which contains a single zoospore;
conjugation of zoospores known in a few species; marine plants, of an olive-brown
color, whose fronds vary greatly in structure, but which all agree in reproducing by
zoospores.
A large group, first correctly defined by Thuret. Previous writers had regarded the structure of the
frond to the exclusion of the organs of reproduction, and the species here included were placed in
different orders. In the Nereis they were placed partly in the Dictyotaceæ, Sporochnaceæ,
Laminariaceæ, Chordariaceæ, and Ectocarpaceæ. The four last orders have been kept as families, but
the true Dictyotaceæ are a distinct order. All the olive-brown sea-weeds of New England, except the
rock-weeds, belong to the present suborder. In no order of plants do the species vary so widely in habit
as in the present. A large number, as the Ectocarpi, are filamentous and resemble in habit the
Cladophoræ. The Laminariæ have expanded flat fronds, and in Macrocystis and Egregia, the most
highly organized of the order, there are stems, distinct leaves, and air-bladders, and in Egregia special
fructiferous leaflets. Many of the species are of microscopic size, but Macrocystis grows to be several
hundred feet long.
SPHÆNOSIPHON, Reinsch.
(From σφην [sphen], a wedge, and σιφων [siphon], a tube.)
Fronds formed of single cells placed side by side so as to form a more or less coherent mass; cells
pyriform-cuneate or oblong-elliptical; contents of cells transformed into a number of very small
spherical bodies (zoospores?).
In the Contributiones ad Algologiam et Fungologiam, Reinsch places the genus Sphænosiphon, of which
he describes nine species, in the order Melanophyceæ. One of the species occurs in fresh water and the
rest are marine. They all form minute spots on other algæ, and consist simply of cells placed side by
side, the whole forming a thin membranous expansion. If the small bodies described and figured by
Reinsch in the interior of the cells are really zoospores, and if the cells themselves are olive-brown, we
must regard the genus Sphænosiphon as the lowest of the Phæosporeæ. The development of the
zoospores has not been observed, and as Reinsch describes the color of some of the species as bluish
green and rose-colored, we must consider the position of the genus to be in doubt. Species of
Sphænosiphon are not unfrequent on our coast, but they have not yet been sufficiently studied. Those
which we have seen are more like the Cyanophyceæ than the Phæosporeæ in color. The following
descriptions, which may apply to some of our species, are taken from Reinsch, l. c.
S. SMARAGDINUS, Reinsch, l. c., Pl. 35, Fig. 4.
Cells pyriform or broadly cuneiform, rounded at the apex, prolonged at the base into a hyaline pedicel;
cells .0168-333 mm long, .0084-112 mm broad at apex, .002 mm at base; color bluish green; base hyaline.
On Plocamium coccineum, Labrador.
On Polysiphonia, Anticosti.
S. OLIVACEUS, Reinsch, l. c., Pl. 36, Fig. 2 a.
Cells pyriform or cuneiform, broadly rounded at apex, contracted at base; color olive-green; cells .013-
24 mm long, breadth .0096-168 mra .
On Ceramium rubrum, Anticosti and Labrador.
S. ROSEUS, Reinsch.
Cells broadly ellipsoidal, placed loosely together, and surrounded by a thick hyaline mucus; rosecolored;
.0041-50 mm long, .004-5 mm broad.
On zoophytes, Labrador.