Family: Trichome (filamentous structure) lacks heterocysts; with equal diameter throughout whole length; no hair-like structure; no branching.
Genus: Trichome without mucous sheath; straight, long, consisting of numerous cells (Illustrations of The Japanese Fresh-water Algae, 1977).
Species: Cells 16-60 μm (usually 40-50 μm) in diam., 3.5-7 μm long (Photomicrographs of the Freshwater Algae, vol. 4, 1985).
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O. princeps
6 x 47 μm
L/W=0.12
Sashi-ohgi
Saitama, 2002
O. princeps
4.5-9 x 47 μm
L/W=0.1-0.2
Higashi-sano
Hakuba
Nagano, 2004
O. princeps
x 47 μm
L/W=
Takano-ike
Mito
Ibaraki, 2003
O. princeps
7 x 47 μm
Ikenokochi m.
Tsuruga
Fukui, 2006
O. princeps
5-8.5 x 41 μm
L/W=0.12-0.21
O-ike park
Yabuki
Fukushima, 2003
O. princeps
4.3 x 38 μm
L/W=0.11
Japan, 1999
O. princeps
6 x 37 μm
L/W=0.16
Sayama
Saitama, 2001
O. princeps
x 28 μm
L/W=
Senjo-ga-hara
Nikko
Tochigi, 2003
O. princeps
4 x 31 μm
L/W=0.1
Futayo-no-ike
Haguro mountain
Yamagata, 2005
O. princeps
v. minor ?
3 x 13 μm
L/W=0.2
near Mihashi Park
Saitama, 2006