ON THE I.AMINARIACEAE OF IIOKKAIDO 
23 
ease between the two by feeling them with his lingers. 
None of the known species is identical with the alga in question, 
so the author proposes here to name it Laminaria coriacea as a new 
species. 
11. Laminaria yezoensis Miyabe, sp. nov. 
(Plates 12 & 13) 
Japanese name. Gohei-kombu. 
Gohei-kombu (Kushiro, Nemuro), Heisoku-kombu (ditto). 
Holdfast composed of a scutate disc, round or elliptical at the 
base, with entire margin and smooth surface while young, be- 
coming irregularly divided along the margin and warty on the 
surface when matured, sometimes united with one or more other 
discs. Stipe solid, rigid, cylindrical, thick in the lower portion, 
tapering upwards, abruptly compressed at the place of connection 
with the blade, often furnished with annual rings in cross section 
thus showing the perennial nature of the plant, forming warty 
outgrowths on surface when old just as in the holdfast, variable 
in length according to the age of the plant, up to 85 cm in length, 
26-30 mm in diameter. Blade entire while very young, becoming 
divided palmately with the advance of growth, long elliptical or 
broad elliptical in entire shape, round at the base, up to 0.7-1. 3 m 
in length, 20-30 cm in breadth ; divided segments of the blade 
3-5, up to as many as 15 in number, sword-shaped, 3 cm in breadth, 
thick near the base, thin in the upper portion ; light brown in 
color ; sporangial sori unknown." 0 
Mucilage ducts absent from stipe but present in blade, arranged 
in one row under each surface near the medulla. Medulla in blade 
thick, composed mainly of vertically arranged filamentous cells. 
Habitat and use. Growing in water 3-4 fathoms in depth, dis- 
tributed along the coasts in the cold current region from Kushiro 
as far northeast as the Kurile Islands. This species is not worth 
harvesting for the market. Its stipe is sometimes utilized of late 
years for making a tobacco-pipe. 
Addenda. About eleven of the known species of the genus 
Laminaria are known to have a palmately divided blade. They 
23) According to Kanda (193S, p. 97), this species becomes soriferous in winter 
and the zoosporangia are formed on both surfaces of the blades. 
