Potamogeton sarmaticus Mäemets

Raab-Straube, Eckhard von & Raus, Thomas, 2025, Euro + Med-Checklist Notulae, 18, Willdenowia 55 (1), pp. 107-144 : 130

Potamogeton sarmaticus Mäemets

+ Cm: Crimea: Sevastopol, Urkusta storage reservoir close to Peredovoye settlement, 44°30'17"N, 33°48'52"E, 14 May 2024, Aleksandrov (SIBS); ibid., Gasfortovskoye storage reservoir, 44°31'51"N, 33°40'54"E, 16 May 2024, Milchakova (SIBS). – The range of Potamogeton sarmaticus encompasses mainly the steppe and foreststeppe zones of E Europe and Kazakhstan plus a few isolated localities in the taiga zone of W Siberia ( Kapitonova 2017). In addition to previously known localities in Ukraine and Russia, the species was recently discovered in Hungary ( GBIF 2023c). For Crimea, P. sarmaticus is given here for the first time. The plants were collected in a coastal zone of storage reservoirs, at a depth of 0.5 to 2 m on silty and silty-sandy substrate, accompanied by some other species of the genus clearly differing from P. sarmaticus . Unlike P. lucens L., P. sarmaticus produces floating leaves (congested, sessile), and the submerged leaves are dull, not shiny, slightly transparent, with conspicuous stripes of air- containing lacunae along the midrib and main lateral veins; and unlike P. gramineus L., P. sarmaticus has elliptic or lanceolate submerged leaves and stipules with 1 or 2 keels ( Mäemets 1978; Mäemets 2001; Kapitonova 2017). The storage reservoirs where P. sarmaticus grows have already existed for many decades. Urkusta (on the Urkusta River) was built in the 1960s and Gasfortovskoye (on the Sukhaya River) in the 1970s, so P. sarmaticus could already have a rather long persistence here. Water in the reservoirs is characterized by calcium hydrocarbonate hardness and assessed as polluted or slightly polluted. Domestic wastewater and irrigated agriculture in adjacent settlements have a significant impact on the water quality. In general, P. sarmaticus is ecologically associated with shallow reservoirs that often dry up ( Klinkova 2006) or small, brackish ponds, and it is believed to have low resistance against anthropogenic transformation of the landscape ( Kapitonova 2017). The species is considered to be rare, with only about two dozen localities throughout its area of distribution ( GBIF 2023c). That is why it is included in the Red Data Books of several regions of the Russian Federation and Ukraine ( Kapitonova 2017). Up to now, together with P. sarmaticus , nine species of Potamogeton L. are known for the spontaneous flora of Crimea ( Yena 2012; Yena & Svirin 2013). A. V. Yena, N. A. Milchakova,

Yu. A. Gavrilova & V. V. Aleksandrov