Potamogeton friesii Ruprecht (1845: 43)

Abbasi, Shabnam, Afsharzadeh, Saeed, Dinarvand, Mehri & Wiegleb, Gerhard, 2017, Synopsis of Potamogetonaceae in Iran with supplements to the Flora Iranica and a new identification key, Phytotaxa 311 (1), pp. 1-21 : 5

Potamogeton friesii Ruprecht (1845: 43) , Fig. 3

Annual, rhizome filiform, stem filiform, slightly compressed. Leaves submersed, linear, green, often with reddish or brownish tinge, 30–50 mm long, 1–2.5 mm wide, (3–)5–7-veined, margins entire, acuminate at apex; stipules not fused, connate, 7–9 mm long, fibrous, splitting into two parts when mature. Spike 7–9 mm long, peduncle 15–20 mm long, as thick as the stem. Tepals 1 mm long, anthers 0.8–0.9 mm long. Carpels 4, fruits 2 mm long. Stele of circular type, endodermis of O-type, interlacunar bundles absent, subepidermal bundles present.

The species is distinguished from morphologically similar Potamogeton pusillus Linnaeus (1753: 127) by having broader, often reddish, 5–7-veined leaves and by the splitting stipules.

Worldwide distribution: —Circumpolar, boreal and temperate regions throughout the northern hemisphere.

Distribution in Iran:—West, Central.

Flowering time: —From spring to autumn.

Specimen examined:— IRAN. Gilan: Astara, Plasi village, - 84 m, 11 Aug 2014, Dinarvand 8230 (Herbarium of the Research Center of Agriculture & Natural Resources of Khuzestan!) ; Isfahan: Deemeh spring, 2133 m, 18 Sep 2014, Abbasi & Afsharzadeh 19635 ( HUI!) ; Bahadoran garden (Zarrin Shahr), 1681 m, 26 Sep 2014, Abbasi & Afsharzadeh 19636 ( HUI!), Chaharmal and Bakhtiari: Gandoman wetland, 2254 m, 27 Aug 2014, Abbasi & Afsharzadeh 19637 ( HUI!), Kurdistan: Kamyaran river , 1000 m, 7 June 2015, Abbasi & Afsharzadeh 20216 ( HUI!) .

Figures

FIGURE 3. P. friesii a. cross section of stem (Scale bar: 100 μm, objective lens 4), b. morphological shape.