20 
K. MIYABE 
whorls. Stipe smooth on surface, solid, complanato-cylindrical 
below, compressed above, up to 5-8 cm in length, 6-8 x 5-7 mm in 
cross section near the base. Blade entire, narrow linear, attaining 
the maximum breadth at the portion a little above the middle of 
the overall length or at a distance of 2/3 of the overall length 
from the base, gradually tapering towards each end, broadly cuneate 
at the base, coriaceous, dark brown in color, sometimes with a 
tinge of green; median fascia 1/5 as wide as the entire breadth 
of the blade ; marginal portions thin, slightly undulate, but thick 
and plane in the lower portion; usually 5-7 fathoms, rarely up to 
12 fathoms, in length, usually 13-16 cm in breadth. Sporangial 
sori developing from the lower portion of the blade upwards, 
covering both surfaces except only along the margins, becoming 
discontinuous in the upper portion, disappearing first from the 
median fascia and forming scattered patches only on the marginal 
portions. 
Mucilage ducts absent from stipe, arranged in one row in 
blade, forming a continuous net-work. Some of the specimens 
collected at Kushiro were found to lack mucilage ducts in the 
median fascia on the under surface. 20 Medulla in the blade is 
rather thin as compared with that of L. angustata, and its filamentous 
cells run in all directions as in the previously described species. 
Habitat. Distributed in the cold current, along the coasts of 
the Kurile Island, Nemuro and Kushiro Provinces. Protected lo- 
calities are not inhabited by the present species. Though it was 
impossible to see the sea bottom from a boat through the usually 
turbid water of the cold current, the present species is supposed 
to inhabit the bottom extending as far as the depth of 4-5 fathoms. 
However, the individuals growing in 3-4 fathoms of water are said 
to be of longer frond and of superior quality. The southern limit 
of this alga’s distribution range does not seem to extend beyond 
Kushiro Harbor. As for its northward distribution, it reaches as 
far north as Shikotan Island and the eastern coast of Etorofu Island, 
but it is unknown at present whether it invades northern regions 
further. 225 It grows most luxuriantly in the area lying between 
the eastern coast of the Nemuro Peninsula and the adjacent islets. 
21) Cf. Foot-note no- 6 on page 5. 
22) This alga has not been known from the northern Kuriles beyond Etorofu Isl. 
{Cf. Nagai, 1940, pp. 75-77). 
