ON THE TAMI.VARIACEAH ON HOKKAIDO 
11 
the author proposes to name it Laminaria ochotensis as a new species. 
Among the species of Hokkaido, L. japonica of Oshima Province is 
that which our new species resembles most closely. However, they 
can be distinguished from each other as they have some differences 
in the shape and inner structure of the blade. 
3. Laminaria f'ra^ilis Miyake, sp. nov. 
(Plate 3) 
Japanese name. Yayan-kombu. 
Yayan-kombu (Muroran), Shio-kombu (ditto), Daiba-kombu (Hako- 
date). 
Holdfast composed of filiform hapteres arising irregularly from 
the lower part of the stipe, arranged somewhat spirally but never 
verticillate, branching seven to nine, or rarely up to thirteen times 
dichotomously, or sometimes tri- or tetra-chotomously. Stipe smooth 
on surface, solid, round or elliptic in cross section at the lower 
portion, markedly flattened at the upper portion, up to ca. 5 cm in 
length, up to 8 x 5-6 mm in diameter. Blade entire, linear-lanceo- 
late, attaining the maximum breadth at the portion below the 
middle of the overall length, round or rarely cordate at the base, 
up to 2.5-3.5 m in length, up to 15-24 cm in width ; median fascia 
1/4 as wide as the whole breadth of the blade ; marginal portions 
thin, slightly undulate, with a row of bullations along both sides 
of the median fascia while young, bullations disappear in mature 
portions ; thin and fragile in substance ; light brown in color, be- 
coming dark brown when dried. Sporangial sori scattered all over 
the surface of the blade, more or less confluent on the median 
fascia but in the form of irregular discontinuous spots on the 
marginal portions, usually present on one surface of the blade and 
absent from the other, but rarely formed on both surfaces, densely 
on one surface and sparsely on the other. The sori begin to develop 
from about the end of August and come to their maturity in Sep- 
tember or October. After that period the blade becomes eroded 
in the upper parts and covered with many epiphytic Hydrozoan 
bodies. 
The stipe is provided with a single row of mucilage canals, 
and its medulla is composed of more or less thick filamentous cells 
running densely, vertically as well as horizontally. The blade is 
