MARINE ALG: OF BEAUFORT, N. C. 457 
throughout the zones on the older portions of the thallus; antheridia and oogonia borne on separate 
plants (dicecious), occurring in sori in concentric bands, as with the tetrasporangia, borne on both sur- 
faces, usually predominantly on the lower surface, oogonia covered by a thin, subpersistent indusium, 
antheridia naked (not covered by indusium); texture membranaceous; color light brown, sometimes 
olivaceous. 
Thallo erecto, plano, expanso, 4-22 cm. longo, 5-37 cm. lato, juvenescente integro, maturascente 
interum atque interum plus minus alte ex marginibus laciniato, segmenta cuneato-spatulata aut flabellata 
formante, aliquando calce incrustato, zonato ab lineis piliferis cum marginibus parallelis, in regionibus 
vetustioribus saepe obscurescentibus, zonis interpilis 1.5-6 mm. latis, basi stipe densa rotundata 3-12 
mm. longa, rhizoideis fulvis dense tecta, disco basali apta; lamina prope revolutas apicales margines 
ex tribus stratis cellularum, per maiorem partem thalli ex quattuor stratis cellularum, ad basim ex sex 
aut octo stratis cellularum constante, cellule epidermis circiter dimidio breviores quam cellulae centrales; 
tetrasporangiis ab indusio tenue et subpersistente tectis, in utraque superficie, plerumque pro maiore 
parte in inferiore superficie, in lineis unis aut duobus cum margine apicale parallelis circiter in una- 
quaque media zona interpilula productis, his lineis hinc inde fractis, tetrasporangiis in partibus adul- 
tioribus thalli per zonas sparsis; antheridiis et oogoniis ab plantis diversis in lineis concentricis sororum 
similiter tetrasporangiis, in utraque superficie, plerumque pro maiore parte in inferiore superficie pro- 
ductis; oogoniis ab indusio tenue et subpersistente tectis, antheridiis nudis (et non ab indusio tectis); 
substantia membranacea; colore dilute fulva, aliquande olivacea. 
North Carolina to Florida; West Indies; Barbados; and Bermuda. 
Beaufort, N. C.: Very abundant on Fort Macon jetties, o to 75 cm. below low tide; extremely 
abundant on Shackleford jetties and breakwaters, o to 1.2 m.; fairly abundant in harbor, June to October; 
one battered specimen on Fort Macon jetty, December, 1908. 
The species here described has often been wrongly referred to P. pavonia J. Ag. or to P. durvillet 
Bory. From the former it is distinguished by the arrangement of the sori, which are in one or two 
rows about the middle of each interpilar zone, instead of in single lines on both sides of each alternate 
piliferous line, asin P. pavonia. From P. durvillei it is distinguished by the epidermal cells, which 
are usually about half as long as the central cells, whereas in P. durvillei they are, in all specimens 
observed by the author, about one-fourth as long as the central cells. Occasionally those of P. vickersie 
are as long as the central cells, the two surfaces of the same section sometimes varying in this respect 
(fig. 22 and Pl. CXIV, figs. 1-3), while those of P. durvillei are said to be half as long as the central 
cells. In any case, however, the epidermal cells of the present species are about twice as long, com- 
pared with the central cells, as those of P. durvillei. In surface view the epidermal cells of P. vickersiea 
are rectangular, having a length of two or more times their width, while those of P. durvillei are usually 
about square. The latter species is also coarser and thicker than P. vickersie, sections showing six 
cell layers throughout most of the lamina and ten cell layers near the base. 
The present species was first figured by Kuetzing (1859, Bd. 9, p. 30, pl. 73, f. 2) under the name 
Zonaria variegata, with the reference ‘‘Ag. spec. I. p. 127.’’ This, however, refers to the true Zonaria 
variegata Mertens, whereas the plant figured by Kuetzing isa Padina. Miss Vickers (1905, No. 66) names 
this species P. variegaia with the reference ‘‘Zonaria variegata Kuetz.’’ Even if the rules of nomen- 
clature allowed the recognition of a Zonaria variegata of Mertens and another of Kuetzing, the name P. 
variegata is rendered invalid by the fact that neither Kuetzing nor Miss Vickers published a description 
of the species. The citation of Bérgesen (1914, p. 205 [49]) to P. variegata (Lamouroux) Hauck seems 
even less warranted. According to Howe (1915, pp. 49-50), Dictyota variegata Lamouroux seems, from 
both the published figures "and the extant specimens of Lamouroux, to have been exclusively Zonaria 
variegata. Hauck’s use of the name Padina variegaia is merely an incidental mention and is founded 
only on a reference to Kuetzing. For both of these reasons this use of the name does not seem to con- 
stitute valid publication. In view of these facts, it has seemed necessary to give a new name to the 
species. 
Our species, however, approaches very near to P. dubia Hauck (1887, p. 45) and may be identical 
with this. In Herb. Hauck there are four good unmounted specimens of P. dubia with a loose label 
written by Hauck. In habit, size, and number of cell layers they resemble the present species; the 
sori are often irregularly scattered over almost the entire surface but in parts are in regular zones just 
above each piliferous line.¢ The available material has not been sufficient to determine whether the 
@ The author is gratefully indebted to Dr. Marshall A. Howe for permission to quote from his notes on P. dubia as found in 
Herb. Hauck, as well as for the opportunity to study portions of two of the original specimens of this species. 
