Potamogeton tenuifolius Raffin.

Material examined.

RUSSIA, Tyumen Reg. - Tobolsk distr. • 9.5 km E of Tobolsk, E of the “Tobolsk-Polymer” site; 58.2200°N, 68.4718°E; channel along the railway, in front of the dam, shallow water; 19 Jul. 2019 (Fig. 1) .

Note.

This species differs from closely related Potamogeton alpinus Balb. by its smaller and narrower leaves (Papchenkov 2007).