26 
K. MIYABE 
Holdfast composed of filamentous hapteres branching several 
times, arising verticillately at the base of the stipe. Stipe solid, 
smooth on surface, cylindrical or complanato-cylindrical below, com- 
pressed above, 3-4 cm in length, ca. 4 mm in diameter near the 
base. Blade linear or lanceolate; median fascia very narrow and 
distinct but not differing from the marginal portion in thickness; 
gyrate puckerings closely set, arranged pinnately along both sides 
of the median fascia meeting the latter at right angles; plane or 
crispate on the margins depending upon the conditions of the 
habitat: thin and coriaceous in substance, very rich in mucilage; 
usually lm, up to 4.5m in length, only 7.5-12cm in breadth at the 
broadest portion. Sporangial sori formed exclusively in the de- 
pressed portions on both surfaces of the blade. 
The stipe has a row of quite irregular and obscure mucilage 
ducts. Kjeleman who described the present species as lacking 
mucilage ducts in stipe seems to have missed seeing them because 
of their small size. The blade has also a row of ducts, which are 
large and distinct. The medulla of the blade is thick. 
Habitat and use. Growing together with Laminaria longissima in 
the cold current region extending from Kushiro as far north as 
the North Kuriles. As this alga is rich in mucilage, one can readily 
get a mucous substance resembling grated yam by stirring chopped 
pieces of its dried blade in hot water. After removing refuse and 
seasoning with soy, it can be served as soup. To store dried blades 
of this alga, people usually braid them tightly. 
Addenda.. The present species varies markedly in the shape of 
blade according to the habitat. At projecting localities exposed 
to rapid tides, it has a narrowly linear blade which is not crispate 
but smooth on the margins (Plate 15), whereas in calm water within 
an arm of the sea it has a broadly lanceolate or elliptical blade 
which is remarkably crispate on the margins. The latter should 
be treated as a variety of the species and the author proposes to 
name it var. crispata Miyabe. (Plate 16). 
