38 
K. MIYABE 
7. Agarum (Boky) Post, et Ruhr. 
Postels et Ruprecht, Illustrationes Algarum, p. 11, 1840. 
Blade is provided at the center with a flattened percurrent 
midrib, with numerous perforations scattered all over the surface, 
lacking cryptostomata and mucilage canals, and slightly crisped in 
the basal portion. 
In the present genus are included four species, 375 of which only 
one is known from Japan. 
Agamm Turneri Postei.s et Ruprecht 
(P late 27) 
Postels et Ruprecht, loc. cit., p. 12, Tab. XXII, 1840. 
Illustration. Turner, Fuci, Tab. LXXV, 1809 ; Postels et Ruprecht, loc. cit., 
Tab. XXII, 1840. 
Japanese name. Aname. 
Zarame. 
Holdfast composed of filiform hapteres arising verticiilately, 
branching several times. Stipe flattened, rigid, 2.3-16.5 cm in 
length. Blade elliptic, only 33-66 cm in length ; midrib usually a 
little broader than, or sometimes as broad as, the stipe ; perfora- 
tions of various sizes scattered promiscuously all over the surface ; 
perforations smooth without dull dentations on the margins ; rigid 
in substance. Sporangial sori in patches scattered over the blade 
on both surfaces." 35 
Habitat. Distributed in the northern part of the Pacific Ocean 
and the northwestern part of the Atlantic. Widely spread all 
along the coasts of Hokkaido and said to occur also in Aomori 
Prefecture. Growing in deep water, making it difficult for a person 
to observe the natural habit of the plant.™ 5 
Addenda. Some of the specimens from Hokkaido have some- 
37) De TONI (1895, pp. 334-335) enumerates four species in Agarum as follows: 
A. Turneri, A. Gmelini Mert., A. pertusum (Mert.) Post, et Rupr., and A. fim- 
briatum HARVEY. 
38) Setchell and GARDNER (1925, p. 615) adopted Agarum cribrosum BORY in 
place of Agarum Turneri POST, et Rupr., and since then that name has generally 
been used in the literature. 
39) TOKIDA (1954, p. 121) reports that he was once able to observe several fronds 
growing on rocks at 2 -3 feet depth beneath the low water mark at Cape Nishinotoro, 
Saghalien, in April 1937. 
