280 
THE SEAWEEDS 
Pollexfenia nana J. Agardh. 
Frond dwarf, 5 cm. to 8 cm. high, palmate or lobate, the lobes small, 
obtuse at the apices, often very wide; the margin is unbroken. Stichidia 
subfasciculate, scattered. Structure and fruit scarcely different from P. 
pedicellata. 
South coast of -Australia. 
DICTYMENIA Greville. 
Frond flat, membranaceous, midribbed, alternately decompound, pin- 
natifid, areolate ; the medullary cells large, 12-sided, colourless, transversely 
set; the cortical minute, irregular, coloured. Cystocarps ovate, stipitate, 
containing a tuft of pear-shaped spores. Stichidia simple or branched, con- 
taining tripartite tetraspores. 
Dictymenia Sonderi Harvey. 
Attachment a large fleshy disc. Stem hard and woody at base, 5 cm. to 
10 cm. long before branching, gradually narrower, less terete, and more 
distinctly winged upwards, passing into a linear, much divided frond. Full 
Fig. 127 .— -Dictymenia Sonderi: a, plant; b, apex of a 
segment, showing midrib, veinlets, false 
areolations and shrubby stichidia; c, small 
portion of same showing surface cellules and 
medullary cells appearing through; d, branch 
from a decompound stichidium; e, tetraspore 
from same. (After Harvey.) 
