130 
PACIFIC SCIENCE, VoL IV, April, 1950 
Fig. 11. Acrothamnion pulchellum J. A g. Part 
of a tetrasporiferous fragment of Harvey’s speci- 
men (Alg. Austr. Exsicc. No. 539D) collected at 
Port Fairy, Victoria, in 1855, showing the sessile 
tetrasporangia with inflated membranes, develop- 
ing on the upper side of the lower portion of the 
pinnae. Three sporangia in various stages of de- 
velopment are shown separately. X 245. 
compound accessory pinnae on the ventral 
side of each of its segments. The sporangia 
mounted in glycerine- water measure 32-48 g 
long and 24—44 g wide, excluding mem- 
branes. Including the outer layer of the mem- 
brane, which is usually swollen to a remark- 
able extent, a sporangium is 86 g long and 
72 g wide and contains a spore mass measur- 
ing 38 g long and 3 6 g wide. The same spo- 
rangium is 52 g long and 48 g wide, includ- 
ing the inner layer of the membrane. A young 
immature sporangium in which the contents 
are undivided and measure 20 g by 18 g is 
38 g long and 34 g wide, including the inner 
layer of the membrane, and 60 g long and 
52 g wide if the outer layer is included. The 
sporangia are sessile, standing on the adaxial 
(upper) side of the basal segment of, usually, 
the lowermost pinnule of the principal and 
accessory pinnae. They divide cruciately by 
two successive divisions, first by a transverse 
wall and second by two walls perpendicular 
to the first as well as to each other. The op- 
posite principal pinnae are slightly bent up- 
ward and toward the dorsal side of the axis, 
so as to form, along with the accessory pin- 
nae, a fence around the axis in order to pro- 
tect the tetrasporangia (cf. Fig. 11). 
Pleonosporium T ohyamanum 
Tokida and Inaba, sp. nov. 
Figs. 12*, b; 13 a, b\ 1 4a, b\ 15 a—c 
Fronde 1—1.5 cm. alta, rhizoidibus longis 
et simplicibus vel ramosis, a cellulis basalibus 
pinnarum inferiorum deorsum vel a cellu- 
lis inferioribus axium principalium lateraliter 
emittentibus adfixa; axibus principalibus in- 
ferne usque ad 300-315 g crassis, ad basin 
in axes nonnulus divisis, ecorticatis, cellulis 
diametro 1.5— 3-plo longioribus, ad septa leve 
inflatis; ramis et pinnis alternis et distichis; 
cellula basali rami quadrata, pinna nulla, cel- 
lula insequenti superiore latere pinna una 
praedita; pinnis simplicibus vel ramosis, 
lineari-lanceolatis, leviter incurvis, apica ob- 
tusis, cellulis apicalibus 22—24 g crassis, cel- 
lulis basalibus pinnarum inferiorum in ramis 
inferioribus inferiore latere pinnulis simplici- 
bus vel ramosis; chromatophoris numerosis, 
brevibus et taeniatis; sporangiis in pinnis et 
pinnulis sessilibus, plerumque in latere su- 
periore secundis, sed raro etiam in latere in- 
feriore sparsis, ellipsoideis, 70-106 g longis 
et 50-78 g lads, sporis pluribus ornatis; an- 
theridiis in latere superiore ramulorum ulti- 
morum secundatis; procarpiis subterminali- 
bus; cystocarpiis terminalibus, ramulis in- 
volucrantibus nullis; cellula glandulina nulla. 
Frond 1—1.5 cm. high, attached to the sub- 
stratum by means of simple or branched rhi- 
zoidal filaments, being produced downwardly 
from the basal cell of the lower branches or 
laterally from the lower segments of the 
main axes; main axes up to 300-315 g diam. 
below, divided into several main axes near 
the base, uncorticated, with cells 1.5-3 times 
