Heterosiphonia japonica Yendo

Also known as H. asymmetrica Hollenberg, H. densiuscula Kylin
Description: Bushy, deep red-brown fronds, to 600 mm long, arising from a basal disc. Axis not always obvious, cylindrical, diminishing in diam. from base to apex. Branching repeatedly distichously pinnate, branches spreading , alternate. Ultimate ramuli bifid or multifid, monosiphonous, sharply pointed.
Habitat: On sand-covered rocks, lower intertidal.
Distribution: currently known from New Quay and Finavarra, Co. Clare, and Carreroe, Co. Galway. Introduced into Ireland, Britain, Norway, Sweden, the Netherlands, France, Spain, and Italy, probably as a result of the transfer of oyster spat. Originally from Pacific where it occurs in Japan, China and Korea, and from Alaska to California.

Species list