no 
DICTYOTAOEA. — Dictyota. 
IV. 
transparent, and the areolations visible with a moderately powerful pocket lens ; 
they vary in shape and in size in different parts of the membrane, and I fear scarcely 
afford a satisfactory specific character. I have not seen fruit on American specimens. 
On the European plant two sorts of fruit have been noticed, on different individuals : 
first, oval clusters of spores, covered at first by a common vesicular membrane ; each 
spore when ripe containing four sporules in a hyaline perispore ; second, solitary, 
roundish, simple spores scattered over the surface. The colour is olivaceous, some- 
times greenish and sometimes brownish. 
3. Dictyota ciliata , J. Ag. ; frond woolly at the base, repeatedly dichotomous, 
broadly linear, membranaceous ; the axils rounded ; laciniae patent, linear, gradually 
narrower towards the extremities ; the margin ciliate, with distant, awl-shaped, 
slender teeth ; the apices obtuse ; spores forming minute sori scattered over the 
middle region of the lamina, leaving an unoccupied space within each margin. 
J. Ag. Symb. 1 . p. 5. Sp.Alg.vol. 1 . p. 93. Kiitz. Sp. Alg. p. 556. (Tab. VIII. A.) 
Hab. On Algae and corals near low-water mark. Florida Keys, abundant at Key 
West, Dr. Wurdemann , Dr. Blodgett , W. H. H., Sfc. (v. v.). 
Boot and lower part of the frond coated with curled, woolly hairs. Fronds densely 
tufted, six to eight or ten inches in length, from an eighth to a quarter-inch in 
breadth, many times dichotomous ; the laciniae gradually narrower in the upper 
dichotomies, ciliated at intervals of a few lines with slender, subulate, tooth-like 
processes. These are more abundant in some specimens than in others. The axils 
are rounded ; the lower ones spread widely and the upper are gradually narrower 
The apices are subacute, or blunted. The sori consist of a few spores, irregularly 
grouped together, and scattered over three-fourths of the surface of the laciniae, 
leaving a narrow unoccupied portion down each margin. Sometimes the frond is 
pitted, (as shown at fig. 4,) the pits apparently caused by the falling off of the 
sori, carrying with them the surface cells. The colour is a clear brown olive, 
greener toward the tops ; and the substance is membranaceous, shrinking in drying. 
Readily known, in most cases, by the ciliate margins ; but sometimes nearly entire^ 
in which case it may be mistaken for D. dichotoma. 
Plate YIII. A. Fig. 1. Plant of Dictyota ciliata ; the natural size ; fig. 2, 
part of a segment, with sori, and fig. 3, part of a segment from which the spores 
have fallen, leaving pits ; both magnified ; fig. 4, small portion of the surface, with 
sorus , showing the small surface cellules, and the lines defining the large internal 
cells : highly magnified. 
4. Dictyota Bartayresiana , Lamour. ; frond scarcely woolly at the base, repeat- 
edly dichotomous, linear, coriaceo-membranaceous, very entire ; the axils rounded ; 
