| 
Apical cells not hairly; axial filament 8-12 μm in diam. | 
 
	 S. tenue
	  μm
	 Inari Park
	 Toyama, 2002 | 
 
	 S. tenue ?
	 10-20 x 5 μm
	 Kayoicho-ike
	 Fukuoka, 2001 | 
 
	 S. tenue ?
	 10-22 x 5 μm
	 Nishi-Urawa
	 Saitama, 2001 | 
 
	 S. tenue ?
	 stock Ti-3 & Ti-5
	 Inari Park
	 Toyama, 2002 | 
 
	 S. tenue ?
	  μm
	 Omiya
	 Saitama, 2001 | 
 
	 S. tenue ?
	  μm
	 Tone river
	 Tsukiyono
	 Gunma, 2003 | 
 
	 S. tenue
	 & st. Taw-12
	 11-15 x 6-10 μm
	 Watarase river
	 Ashikaga
	 Tochigi, 2004 | 
 
	 S. tenue
	 15 x 9 μm
	 Furu-tone river
	 Kasukabe
	 Saitama, 2004 | 
 
	 S. tenue
	 7-27 x 6-10 μm
	 Tama river
	 Chofu
	 Tokyo, 2004 | 
 
	 S. tenue
	 10-30 x 6-10 μm
	 Karasu river
	 Takasakis
	 Gunma, 2004 | 
 
	 S. tenue
	 8-23 x 6-13 μm
	 Kurome river
	 Asaka
	 Saitama, 2004 | 
 
	 S. tenue
	  μm
	 Showa-machi g.p.
	 Showa
	 Saitama, 2006
	
   | 
 
	 S. tenue
	  μm
	 Jinbei-numa
	 Motono
	 Chiba, 2006
	
   | 
 
	 S. tenue
	 10-25 x 6-7 μm
	 drainage ditch
	 Kawagoe
	 Saitama, 2007
	
   | 
| 
Apical cells hairly; axial filament 5-8 μm in diam.; no constriction at cell-cell junction | 
 
	 S. aestivale
	  μm
	 Itakura Central Park
	 Itakura
	 Gunma, 2003 | 
 
	 S. aestivale ?
	 17-24 x 9.5 μm
	 Tsukuba
	 Ibaraki, 2000 | 
 
	 S. aestivale ?
	  μm
	 Shiroyama Park
	 Okegawa
	 Saitama, 2006
	
   | 
| 
Apical cells hairly; axial filament 10-15 μm in diam.; slight constriction at cell-cell junction | 
 
	 S. subsecundum
	 13-25 x 4-9 μm
	 Watarase river
	 Ashikaga
	 Tochigi, 2004 | 
 
	 S. subsecundum ?
	  μm
	 Ootagaya numa
	 Tsurugashima
	 Saitama, 2003 | 
 
	 S. subsecundum ?
	  μm
	 Mikazuki-bashi
	 Ushiku
	 Ibaraki, 2002 | 
 
	 S. subsecundum ?
	  μm
	 Onnenai
	 Kushiro marsh
	 Hokkaido, 2005 | 
 
	 S. subsecundum
	 20-35 x 4-10 μm
	 Ohnuma
	 Nasu-shiobara
	 Tochigi, 2006
	
   | 
 
	 S. subsecundum ?
	  μm
	 Binnuma-gawa
	 Fujimi
	 Saitama, 2006
	
   | 
| 
??? | 
 
	 S. lubricum ?
	  μm
	 Tsuki river
	 Ranzan
	 Saitama, 2003 | 
 
	 Stigeoclonium sp. ?
	  μm
	 Akebono-yama A.P.
	 Kashiwa
	 Chiba, 2002 | 
 
	 Stigeoclonium sp. ?
	  μm
	 water treatment c.
	 Sakado
	 Saitama, 2004 | 
 
	 Stigeoclonium sp. ?
	  μm
	 Ikenokochi marsh
	 Tsuruga
	 Fukui, 2004 |