Penium Iibellula (Focke) Nordst. in W. & G.S.West = Closterium closterioides (Ralfs) A.Louis & Peeters

Penium adelochondrum Elfving in W. & G.S.West = Actinotaenium adelochondrum (Elfving) Teiling

Penium clevei Lundell = Actinotaenium clevei (P.Lundell) Teil.

Penium coronatum (Bréb.) Rabenh.

Penium crassiusculum de Bary = Actinotaenium crassiusculum (de Bary) Teiling

Penium cruciferum (de Bary) Wittr. in Wittr. & Nordst. = Actinotaenium cruciferum (de Bary) Teiling

Penium cucurbitinum (Bisset) W. & G.S.West

Penium curtum (Bréb.) Bréb. in Kütz. = Actinotaenium curtum (Bréb.) Teiling ex Ruzicka & Pouzar

Penium cylindrus (Ehrenb.) ex Bréb. in Ralfs

Penium didymocarpum P.Lundell

Penium exiguum W.West

Penium inconspicuum West = Actinotaenium inconspicuum (W. & G.S.West) Teiling

Penium jenneri Ralfs = Cylindrocystis brebissonii (Menegh. ex Ralfs) de Bary var. jenneri (Ralfs) Reinsch & Kirchn. ex Hansg.

Penium libellula (Focke) Nordst. = Closterium closterioides (Ralfs) A.Louis & Peeters var. closterioides Ruzicka

Penium libellula (R.Roy & Bisset) Ruzicka

Penium margaritaceum (Ehrenb.) ex Bréb. in Ralfs

Penium minutissimum Nordst. = Actinotaenium minutissimum (Nordst.) Teiling

Penium minutum

Penium minutum (Ralfs) Cleve

Penium mooreanum W.Archer = Actinotaenium mooreanum (W.Archer) Teiling

Penium navicula Bréb.

Penium navicula Bréb. = Closterium navicula (Bréb.) Lütkem. var. navicula Ruzicka

Penium navicula Bréb. in W. & G.S.West = Closterium navicula (Bréb.) Lütkem.

Penium polymorphum (Perty) Perty

Penium rufescens Cleve = Actinotaenium rufescens (Cleve) Teiling

Penium silvae-nigrae Rabanus

Penium spirostriolatum J.Barker

Penium suboctangulare W.West = Actinotaenium minutissimum (Nordst.) Teiling var. suboctangulare (W.West) Teiling

Penium subtile W. & G.S.West = Actinotaenium subtile (W. & G.S.West) Teiling

Penium trabecula (Ehrenb.) ex Nägeli

Penium truncatum Bréb. in Ralfs = Actinotaenium truncatum (Bréb.) Teiling in Ruzicka & Pouzar