298 
THE SEAWEEDS 
ENANTIOCLADIA Falkenberg. 
Frond erect, margins all more or less winged and very regular; axis 
polysiphonous, composed of cells around five central siphons, the cortex 
thick and formed of minute cellules. Primary ramuli long, regular, apices 
curled, branched laterally, dichotomous; the ramelli often secund, simple 
and denticulate, rising from the ventral and dorsal part of the frond or 
from the surface of the marginal teeth singly or in groups. Cystocarps 
subglobose, pericarp very thick. Tetrasporangia numerous in the stichidia. 
Stiehidia mostly crowded on end of the ramuli. 
Enantiocladia axillaris F alkenberg. 
Primary frond thick, costate, denuded of wings, as if stipitate; ramuli 
lateral, slender, simple. Tetrasporangia sometimes on the apices of the 
branches, other times carried in the stichidia. Stichidia grouped in the 
axils of the ramuli. Colour red. 
West Australia (King George Sound). 
VIDALIA Lamouroux. 
Fronds erect, compressed, often spirally twisted, serrated, irregularly 
pinnate; much branched, ribs immersed with veins running out into the 
serrations; obliquely transversely zonate. The interior cells arranged in 
two parallel rows, forming long hexagonal zones, ascending obliquely from 
the costa; the outer cortical cells very minute and densely packed; five 
central siphons. Fruit developed on the margins of the serrations or the 
much changed ramelli. Cystocarps subglobose. Carpospores pyriform in 
the terminal articulations of the filaments. Antheridia subglobose, in rows 
on the convex side of the serrations. Stichidia fasciculate, regular, lanceo- 
late, linear, curved. Tetrasporangia in two longitudinal rows. Colour red ; 
substance cartilaginous. 
Vidalia spiralis Lamouroux. 
Frond 15 cm. to 20 cm. long, branched, irregularly curved or spirally 
twisted, 4 mm. to 6 mm. in diameter, tough and hard, corrugated, obscurely 
winged, densely clothed throughout with lateral branches. Branches mem- 
branaceous, thin, 10 .cm. to 20 cm. long, 3 mm. to 7 mm. broad, preserving 
nearly the same breadth throughout, rather narrow at the apex, pinnatifid 
or; bipinnatifid; the laciniae very erect, linear, spirally twisted, sharply 
serrate, the serratures about 2 mm. apart, with rounded interstices. 
Stichidia forming interrupted lines upon the costa, very dense, lanceolate, 
involute, containing a double row of tetraspores. Cystocarps globose, 
pedicellate, issuing from the costa, or more frequently terminating the 
marginal teeth. Colour reddish-browni when dry. 
South Australia (Holdfast Bay, Encounter Bay, Investigator Strait, 
Spencer Gulf), Western Australia. 
OSMUND ARIA Lamouroux. 
Frond proliferous. Phvllodia flat, linear, midribbed, very rough on both 
sides with wart-like or spine-like processes; interior cellules large and 
