| 
1) Cell body moderately curved; L/W > 7 | 
 
	 var. moniliferum
	 430 x 53 μm
	 L/W=8.1
	 Onnenai
	 Kushiro marsh
	 Hokkaido, 2005 | 
 
	 var. moniliferum
	 320 x 43 μm
	 L/W=7.4
	 Oura central p.
	 Oura
	 Gunma, 2006
	
   | 
 
	 var. moniliferum
	 280 x 35 μm
	 L/W=8.0
	 near Kodanuki m.
	 Fujinomiya
	 Shizuoka, 2005 | 
 
	 var. moniliferum
	 280 x 37 μm
	 L/W=7.6
	 Oyomi marsh
	 Hakuba
	 Nagano, 2006
	
   | 
 
	 var. moniliferum
	 222 x 30 μm
	 L/W=7.4
	 near Oyomi marsh
	 Hakuba
	 Nagano, 2004 | 
 
	 var. moniliferum
	 240 x 34 μm
	 L/W=7.1
	 Saitama, 2003 | 
| 
2) Cell body moderately curved; L/W = 6-7; body > 300 μm | 
 
	 v. moniliferum
	 13 samples
	 260-380 μm
	 2002-2008 | 
 
	 v. moniliferum
	 13 samples
	 260-380 μm
	 2002-2008 | 
 
	 v. moniliferum
	 13 samples
	 260-380 μm
	 2002-2008 | 
 
	 v. moniliferum
	 13 samples
	 260-380 μm
	 2002-2008 | 
| 
3) Cell body moderately curved; L/W = 6-7; body < 300 μm | 
 
	 v. moniliferum
	 24 samples
	 208-290 μm
	 1998-2006 | 
 
	 v. moniliferum
	 24 samples
	 208-290 μm
	 1998-2006 | 
 
	 v. moniliferum
	 24 samples
	 208-290 μm
	 1998-2006 | 
 
	 v. moniliferum
	 24 samples
	 208-290 μm
	 1998-2006 | 
| 
4) Cell body moderately curved; L/W=5-6 | 
 
	 v. moniliferum
	 11 samples
	 190-337 μm
	 1998-2006 | 
 
	 v. moniliferum
	 11 samples
	 190-337 μm
	 1998-2006 | 
 
	 v. moniliferum
	 11 samples
	 190-337 μm
	 1998-2006 | 
 
	 v. moniliferum
	 11 samples
	 190-337 μm
	 1998-2006 | 
| 
5) Cell body strongly curved; inner side concave; both ends long & tapered | 
 
	 var. concavum
	 or C. ehrenbergii ?
	 371 x 49 μm
	 L/W=7.6
	 Fujimi
	 Saitama, 2004 | 
 
	 var. concavum ?
	 or C. leibleinii ? 
	 228 μm
	 L/W=7.4
	 Japan, 1999 | 
 
	 var. concavum ?
	 or C. leibleinii ? 
	 240 x 35 μm
	 L/W=6.8
	 Kawagoe
	 Saitama, 2002 | 
 
	 var. concavum ?
	 or C. leibleinii ? 
	 220 x 33 μm
	 L/W=6.7
	 Kodama town
	 Saitama, 2003 | 
 
	 var. concavum ?
	 205 x 28 μm
	 L/W=6.3
	 Uruguay, 1999 | 
| 
6) Cell body short; L/W < 5 | 
 
	 C. moniliferum ?
	 155 x 33 μm
	 L/W=4.7
	 Shakujii Park
	 Tokyo, 2001 | 
 
	 var. moniliferum
	 or C. leibleinii ?
	 230 x 41 μm
	 L/W=5.6
	 both ends inverted
	 near City Hall
	 Fujimi
	 Saitama, 2004 | 
| 
7) Cell body long; L/W > 8 | 
 
	 C. moniliferum ?
	 270 x 30 μm
	 L/W=9.0
	 Ikenokochi marsh
	 Tsuruga
	 Fukui, 2004 |