Family: Colonies of a fixed number of cells (4, 8, 16, 32, or more) arranged 2- or 3-dimensionally; cells spherical, ellipsoidal, polygonal, etc. in shape; chloroplasts 1 or several, plate-like in shape, with 1 pyrenoid; asexual reproduction by autocoenobium (Illustrations of The Japanese Fresh-water Algae, 1977).
Genus: Colonies spherical, with inner empty space; cells attached to each other by a protrusion of cell wall, arranged in a single layer; cell body mostly spherical with some conical or grobular bulges; chloroplasts cup-shaped with a pyrenoid; reproduction by asexual coenobium (Illustrations of The Japanese Fresh-water Algae, 1977).
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C. sphaericum
sphericum ?
4 samples
1997-2003
C. astroideum
21 samples
1998-2004
C. astroideum ?
1998-2004
C. cambricum
= C. pulchrum
21 samples
1998-2006
C. reticulatum
22 samples
1999-2008
C. morus
15 samples
1998-2008
C. microporum
5 samples
Japan, 1999-2001
C. polychordum
5 samples
2001-2006
C. proboscideum
colony 39 μm φ
Tobai
Kawashima
or Kawajima
Saitama, 2002
C. proboscideum
colony μm φ
Doman-green Park
Nishi-Urawa
Saitama, 2003
C. proboscideum
colony μm φ
Nogyo Fureai p.
Toride
Ibaraki, 2008