Potamogeton lacunatus Hagstr.

Material examined.

RUSSIA, Tyumen Reg. - Tobolsk distr. • 2.75 km NE of the microdistrict Mendeleevo (city of Tobolsk), site "Chistoe boloto", sandy quarry in 1.8 km E of Uvat tract; 58.3129°N, 68.3699°E; watered excavation; 1 Jul. 2019; IBIW. • southern outskirts of the village Baigara; 58.0266°N, 68.8422°E; lake on the right bank of the Irtysh River, shallow water near the shore, tightly; 3 Jul. 2019; IBIW (Fig. 1) .

Note.

The species differs from Potamogeton berchtoldii Fieb. by its spatulate upper leaves and a wide strip of lacunae, occupying the entire space between the central and lateral veins (Papchenkov 2001, 2007). For the Asian part of Russia, the species was not previously recorded (Durnikin 2012).