IV. 
FUCACE2E. — Piiyllospora. 
61 
leaves oblong-elliptical, acuminate, ribbed, obsoletely glandular, serrate or sub- 
entire ; air-vessels spherical, pointless, on very short stalks ; receptacles warted, 
two-edged, twisted, spinous-toothed, forked, their branches at length pedicellate, 
crowded in the axils.” J. Ag. Sp. Alg.vol. 1, p. 322. 
Hab. In the Atlantic, from the shores of Mexico to those of Newfoundland. J. 
Agar dli. 
I am not acquainted with this species. 
7. Sargassum Jilipendula , Ag ; “ stem filiform, very smooth ; leaves narrow- 
linear, ribbed, with a single row of glands at each side the rib, serrated, the upper- 
most very narrow and nearly entire ; air-vessels spherical, pointless, nearly without 
glands, on compressed stalks longer than themselves ; receptacles cylindrical, 
warted, unarmed, paniculate on a long axillary ramulus, the lowermost stalked, the 
upper confluent.” J. Ag. Sp. Alg. vol. 1 ,p. 314. 
Hab. The Gulf of Mexico, J. Agardh. 
Unknown to me. 
II. PHYLLOSPORA. Ag. 
Boot branching. Frond distichous. Branches flat or compressed, fringed with 
marginal leaves. Leaves nerveless, undivided, tapering at base into sub-distinct 
petioles, marginal, distichous, vertical. Air-vessels formed by transformation of a 
portion of the leaf into a bladdery vesicle. Beceptacles leaf-like, having numerous 
pores beneath which are placed the spherical conceptacles (or spore cavities). 
Spore-cavities diclinous. Spores several in each conceptacle, to whose walls they are 
attached, obovoid, subsessile, having a hyaline perispore. Antlxeridia ellipsoidal, 
racemose. Paranemata long, simple, clothing the walls of the conceptacle. 
A genus consisting of two species formerly placed in Macrocystis , of which they 
have in some respects the habit, but from which they essentially differ in fructifica- 
tion. The type of structure is in many respects lower than that of Sargassum • 
the fruit-leaves or receptacles scarcely differing from the ordinary leaves, except in 
being of somewhat smaller size, and thicker substance. The disposition of the 
branches and leaves is so unlike that of any other N. American Alga, that there 
