Image © Marien van Westen
Pleurotaenium nodulosum. Notice large cell size and small apical granules.
Cell dimensions (L x B): 500 x 60 µm
Pleurotaenium nodulosum is a stout Pleurotaenium species, much resembling Pl. coronatum*. The main difference is in the apical granules: remarkably stout in Pl. coronatum, rather discrete or even wanting in Pl. nodulosum. Moreover, contrary to Pl. coronatum, apices in Pl. coronatum are usually slightly attenuate. Lateral sides are markedly undulate, at least in the basal half of the semicells. In the Netherlands, Pl. nodulosum is occasionally encountered in slightly acidic, mesotrophic water bodies, particularly in shallow fen hollows.
* In the flora by West & West (1904) Pl. nodulosum is considered just a variety of Pl. coronatum.
Cell of Pl. nodulosum showing undulate lateral margins, slightly tapering to the apices. Mouse over: Semicell of Pl. nodulosum showing apical granulus in more detail.
Dead semicell of Pl. nodulosum showing punctation of the cell wall (in mouse over).