454 BULLETIN OF THE BUREAU OF FISHERIES. 
Family DICTYOTACE (Lamouroux) Zanardini. 
_ Characters of the order. 
About 120 species, all marine, mostly in warm seas, one species extending to 
Scandinavia. 
EEY TO GENERA. 
a. Frond growing by means of single initial cells situated at the apices............ 5. Dictyota (p. 460). 
aa. Frond growing by means of a group or groups of marginal cells situated at the apices............ b. 
b. Frond zonate by concentric lines of growth, in the neighborhood of which the spor- 
angia and gametangia are developed; fan shaped... .. 0.0.1... seer ee cee ct emcee tncepeneneee ie 
c. Hairs lacking on the sterile portions of the frond .................+.+.4-- . Zonaria (p. 454). 
cc. Hairs present on the sterile portions of the frond.... 2.0.2... 00....-24005 2. Padina (p. 455). 
bb. Frond uniform, concentric lines of growth lacking; repeatedly dichotomous. ................. d. 
Ae MIGEt DAG KINO Sie iu neict rntc pice cisic a ieeieiaate marie cierto eee 3- Spatoglossum (p. 458). 
dd. Midrib present....... EE ens mieRemiesenie creme meen tess cers etnias 4. Dictyopteris (p. 459). 
Genus 1. Zonaria Agardh. 
Zonaria, Agardh, 1817, p. XX (in part), 
Frond flat, fan shaped, often ascending from a prostrate lower part, growing by 
groups of cells along the apical margins, forming rather vague, scattered zones, divided 
into more or less narrow segments, often narrowed at the base of the frond and of the 
separate segments to a subcylindrical, stemlike portion densely covered by short, brown, 
rhizoidal filaments, this stemlike structure often continued as midribs for short distances 
on the flattened segments of the lamina; cortex composed of a single layer of cells 
arranged in pairs forming longitudinal lines radiating like a fan, each row of paired 
cells corresponding to a single row of interior cells; inner stratum consisting of several 
layers of cells; sporangia pear shaped, borne in more or less prominent sori, forming 
scattered, spotlike patches on one or both surfaces of the thallus, covered by the cuticle 
as an indusium which is burst as the sorus is elevated and soon disappears, sporangia 
often surrounded by numerous club-shaped, segmented paraphyses, bearing 8 spores; 
sexual reproduction unknown. 
About 15 species in warm and tropical seas. 
KEY TO SPECIES. 
Frond entire or nearly so, stipe usually 3 to5 mm. long...................... 1. Z. variegata (p. 454). 
Frond much divided, stipe usually 1 to 5 cm. long... ........ 2-2. se see e eee eee ees 2. Z, flava (p. 455). 
1. Zonaria variegata (Lamouroux) Mertens. Pl. XCI, fig. 2. 
Dictyota variegata, Lamouroux, 1813, pl. s, f. 7. 
Zonaria variegata, Mertens, in Martins, 1828, p. 6, pl. 2, f. 2. 
Gymnosorus variegatus, De Toni, 1895, p. 227- 
P. B.-A. Nos. 778 (Gymnosorus variegatus.), 2028. 
Frond flat, fan shaped, rather erect on a short stipe, 3 to 9 cm. tall, 4.5 to 14 cm. wide, stipe 3 to 15 
mm. (usually 3 to 5 mm.) long, thallus entire or more or less lobate, marked by variegated markings 
radiating from the base and by more or less conspicuous, distant, concentric zonations parallel with the 
apical margin; sori elliptical, forming broken lines or scattered spots between the zonations; texture 
thin membranaceous or parchmentlike; color olive brown to dark reddish brown. 
Florida and West Indies to Brazil; Barbados; Bermuda; Canary Islands; Australian region; Red 
Sea; Hawaii; Philippines. 
Bogue Beach, Beaufort, N. C., one specimen April, 1908, two specimens February, 1909, all sterile. 
In this species the concentric zonations are sometimes fairly conspicuous, sometimes invisible to 
the naked eye. It is easily distinguished from the following species by its smaller size, shorter stipe, 
