Species [ var. depressum ]: Cell body small in size, wider than length, 33-50 μm long, (36.5-47.5)-50 μm wide, isthmus 10-15 μm wide; semicells depressed ellipsoid, with slightly flattened apex, side view circular, apical view elliptical, with a single pyrenoid.
[ var. minor W. et G.S. West ]: Cell body smaller than var. depressum, 21-28 μm long, 21-25.3 μm wide, isthmus 4.3-8.4 μm wide; semicells elliptical diamond-shaped.
[ var. achondrum (Boldt) W. et G.S. West ]: Cell body 36-51 μm long, 40-52 μm wide, L/W=1.0; isthmus 11-17 μm wide; semicells hexagonal ellipsoid, apex broad, flattened (Illustrations of The Japanese Fresh-water Algae, 1977).
Google Image Search
Similar species -- >> C. bioculatum; C. contractum;
var. depressum: Semicells depressed ellipsoid, 33-50 μm long, 36-50 μm wide
C. depressum
v. depressum
30 x 30 μm
Uruguay, 1999
C. depressum
or C. contractum ?
38 x 30 μm
Aka-ike
Madarao highland
Niigata, 2006var. minor: Semicells elliptical diamond-shaped, 21-28 μm long, 21-25 μm wide
C. depressum
v. minor ?
26 x 24 μm
Kenashitai
Hakkoda mountain
Aomori, 2005
C. depressum
v. minor ?
24 x 21 μm
Imou bog
Toyohashi
Aichi, 2005
C. depressum
v. minor ?
28 x 24 μm
Imou bog
Toyohashi
Aichi, 2006
C. depressum
v. minor ?
28 x 25 μm
23.5 x 21 μm
near Uba-ga-daira
Nasu
Tochigi, 2006var. planctonicum: Semicells reniform, 25-26 μm long, 25-26 μm wide
C. depressum
v. planctonicum ?
23 x 22 μm
Iroha-numa
Zao mountain
Yamagata, 2005
C. depressum
v. planctonicum
22 x 19 μm
Iroha-numa 2
Zao mountain
Yamagata, 2006
C. depressum
v. planctonicum ?
26.5 x 23 μm
Kashibaru marsh 5
Karatsu
Saga, 2006
C. depressum
v. planctonicum ?
28 x 25 μm
Shibu-ike
Shiga highland
Nagano, 2005f. minuta: Semicells elongated ellipsoidal, 22.5 μm long, 28 μm wide
C. depressum
f. minuta
22 x 25 μm
Karakemi marsh
Omachi
Nagano, 2006
C. depressum
f. minuta
24 x 25 μm
Ohnuma
Nasu-shiobara
Tochigi, 2007
C. depressum
f. minuta
μm
Kannon-numa 10
Nasu-shiobara
Shimogo, 2008
C. depressum
f. minuta
μm
Kannon-numa 11
Nasu-shiobara
Shimogo, 2008