38. 
39. 
40. 
4l. 
42. 
129 
Frond with a midrib ite sisfe sas Dictyopteris ...p.75 
Frond without a midrib ... att Soc we  Dicioia -...p.75 
Small plants less than 2 inches long, thin and wiry, growing on 
the leaves of Zostera ... ete Phyllitis zosterifolia ...p.58 
Thallus branched mostly at the base, narrow, whip-like ; 
composed of a solid core of large and small cells surrounded 
by a cortical mantle of short, narrow, closely packed, radial 
assimilatory filaments soc doc ... Chordavia ...p.70 
Thallus without complete mantle of radial assimilatory filaments 40 
Thallus traversed by a distinct axial row of cells (transverse 
section of main axis shows a single, thick-walled, though not 
necessarily large cell in the middle); plant often covered 
by brush-like tufts of fine silky hairs ... Desmarestia ...p.55 
Thallus without an axial row of cells... Ee wae aon eal 
Cylindrical branched plant, beset with ovoid bodies, crowned 
with a tuft of hairs and containing branched filaments 
bearing unilocular sporangia ... Bae Sporochnus ...p.71 
Plant without ovoid sporangia-containing bodies soc eA 
Thallus much branched, forming bushy plant from 6-8 inches long ; 
unilocular sporangia sunk in the cortical tissue, not protruding 
Dictyosiphon ...p.56 
Thallus hollow ; branches opposite or in whorls; -cells large ; 
surface cells transformed into unilocular sporangia in whorls, 
making transverse bars visible to the naked eye Striaria.:.p.58 
Thallus at first solid, later hollow; cells of the axis increasing 
in size towards the periphery, but covered externally by 
a single layer of small cells; unilocular sporangia in sori, 
accompanied by groups of club-shaped filaments, forming 
minute dark-coloured warts over the surface Stilophova_ ...p.70 
Thallus solid, much branched, eventually covered by whorls of 
tufted hairs, from which arise as lateral branches bead-like 
chains of unilocular sporangia ... ae Arthrocladia ...p.64 
RHODOPHYCEAE 
. Thallus encrusted with calcium 
-Thallus not encrusted with calcium 
Thallus expanded horizontally, encrusting rock or other algae; 
attached by the whole under surface, or with free margins, or 
attached at one point only ; irregular coral-like branches 
without regular constrictions may arise from the horizontal 
portion Ses ae Baie =oe See sige Sai 
Thallus not expanded horizontally, but erect, branched and 
regularly constricted into an articulated thallus Corallina ...p.104 
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