Family: Trichome (filamentous structure) with heterocysts; with equal diameter throughout hole length;
no branching; heterocysts intervening or at base.
(Illustrations of The Japanese Fresh-water Algae, 1977).
Nodularia spumigena Mertens var. spuigena (or var. major (Kützing) Bornet et Flahault),
cell body 3-5 μm long, 10 μm wide, L/W=0.3-0.5,
x 640, Shimizu-daira, Nasu town, Tochigi Pref., Japan, September 10, 2005, collected by Eizaburo Tsukii, photo by Y. Tsukii
94 μm; x 640
Cell body 3.5-6 μm long, 11 μm wide, L/W=0.3-0.5, x 640