IV. FUCACE^.— Phtllospora. 61 



leaves oblong-elliptical, acuminate, ribbed, obsoletely glandular, serrate or sub- 

 entire ; air-vessels spherical, pointless, on very short stalks j receptacles warted, 

 two-edged, twisted, spinous-toothed, forked, their branches at length pedicellate, 

 crowded in the axils." /. Ag. Sp. Alg. vol. 1, p. 322. 



Hab. In the Atlantic, from the shores of Mexico to those of Newfoundland. /. 

 Agardh. 



I am not acquainted with this species. 



7. Sargassum JiUpendula, 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." /. Ag. Sp. Alg. vol. I, p. 314, 



Hab. The Gulf of Mexico, J. Agardh. 



Unknown to me. 



n. 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. Receptacles 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. Antheridia 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 



