Pacific Species of Antithamnion — Tokida and INABA 
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Fig. 1. Antithamnion basisporum Tokida and Inaba, sp. nov.: a, middle portion of a main branch, 
showing tetrasporangia and gland cells; b, apical portion of a main branch; c, part of a branch, show- 
ing that two of the pinnae bear a sporangium on each of two lowest cells, and that one pinna bears on 
its lowest cell a pinnula together with a sporangium, a and c, X 150; b, X 350. 
tentibus adfixis, superne erectis et ca. 2 mm. 
aids; ramis in plerusque a cellulis basalibus 
pinnarum vel raro a cellulis axialibus ramo- 
rum ipsis emittentibus, usque ad 20-32 /x 
crassis, cellulis diametro 1-4-plo longioribus; 
pinnis simplicibus vel raro semel divisis, apice 
rotundatis, 7-14 (-l6)-cellulanbus, usque 
ad 14 /jl crassis, cellulis diametro 1-3-plo 
longioribus, cellulis glandulinis supra unam 
cellulam lateraliter sitis ornatis; chromato- 
phoris paucis, taeniatis; tetrasporangiis in cel- 
lulis basalibus pinnarum sessilibus, 28-38 [x 
X 56-64 /x, cruciatim divisis; spermatangiis 
et ramulis carpogonatis ignotis. 
Frond sparsely branched and oppositely 
pinnate; main axis creeping below, attached 
to the substratum by means of short, simple 
rhizoids, 16-26 fx diam., arising from the 
basal cells of pinnae, erect above, ca. 2 mm. 
high; branches usually produced from the 
basal cells of pinnae or rarely from the axial 
cells of the main branch itself, up to 20-32 /x 
