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potamot de l'ilenissei, Yenisei River pondweed, Yenissei River pondweed

northern snail-seed pondweed, potamot spirille, spiral pondweed

Cauline stems

compressed-filiform, without spots, to 50 cm;

glands white, 0.3–0.5 mm diam.

compressed, without spots, 5–40 cm;

glands absent.

Turions

lateral, common, 3.5–9.5 cm × 2–5 mm, soft;

leaves ± 2-ranked;

outer leaves 3–4 per side, base not corrugate;

inner leaves undifferentiated.

absent.

Leaves

submersed, ± spirally arranged, sessile, flaccid;

stipules deliquescent, inconspicuous, convolute, free from blade, pale brown, not ligulate, 1–2 cm, not fibrous, not shredding, apex obtuse;

blade dark green, linear, not arcuate, 3.5–9.5 cm × 1.5–2 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, rounded or nearly acute to mucronate, lacunae in 1–2 rows each side of midvein;

veins 9–17.

both submersed and floating or floating absent, ± spirally arranged.

Floating leaves

petiolate;

petioles continuous in color to apex, 5–25 mm;

blade adaxially light green, oblong to obovate, 0.7–—3.5 cm × 2–13 mm, base tapered to rounded, apex obtuse, rounded;

veins 5–15.

Submersed leaves

sessile, lax;

stipules persistent to deliquescent, inconspicuous, convolute, adnate to blade for ½ stipule length, reddish brown to light green, ligulate, 2–12 mm, not fibrous, not shredding at tip, apex obtuse;

blade red-brown to light green, linear, not arcuate, 0.8–8 cm × 0.5–2 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, obtuse to acute, lacunae present, a broad band each side of midvein;

veins 1–3.

Inflorescences

unbranched, emersed;

peduncles not dimorphic, axillary, erect, cylindric, 1.7–3.5 cm;

spikes not dimorphic, cylindric, 10–30 mm.

unbranched;

peduncles dimorphic, submersed axillary, recurved, clavate, 0.5–3 mm, emersed axillary or terminal, erect to recurved, slightly clavate, 4–27 mm;

spikes dimorphic, submersed capitate, 2–5 mm, emersed ellipsoid to cylindric, 4–13 mm.

Fruits

sessile, reddish brown, oblong-obovoid, compressed, abaxially ridged, not laterally keeled, 3–4 × 1.5–2 mm;

beak nearly erect, 0.3–0.5 mm;

sides without basal tubercles;

embryo with 1 full coil.

sessile, greenish brown, somewhat orbicular, compressed, abaxially winged, laterally winged, 4–13 × 1.3–2.4 mm, lateral wing with blunt tips;

beak absent;

sides without basal tubercles;

embryo with more than 1 full spiral.

Rhizome(s)

absent.

present.

Potamogeton subsibiricus

Potamogeton spirillus

Phenology Fruiting early summer–late summer. Flowering mid summer–late fall.
Habitat Shallow water of ponds and lakes Neutral to acidic waters of ponds, lakes, and streams
Elevation 0–915 m (0–3000 ft) 0–400 m (0–1300 ft)
Distribution
from FNA
AK; MB; NT; NU; ON; QC; YT; Siberia
[BONAP county map]
from FNA
CT; IA; MA; ME; MI; MN; NE; NH; NJ; NY; OH; PA; RI; VT; WI; MB; NB; NF; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

The This is the firstone of three Potamogeton species in the flora area with dimorphic inflorescences. It can be separated from the other two species because its submersed leaf blades have broad lacunae, extending nearly from the midvein to the margin, and its fruits have lateral wings with blunt points along it. along them.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 22. FNA vol. 22.
Parent taxa Potamogetonaceae > Potamogeton Potamogetonaceae > Potamogeton
Sibling taxa
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. confervoides, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pulcher, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. strictifolius, P. tennesseensis, P. vaseyi, P. zosteriformis
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. confervoides, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pulcher, P. pusillus, P. richardsonii, P. robbinsii, P. strictifolius, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
Synonyms P. porsildiorum
Name authority Hagström: Kongl. Svenska Vetenskapsakademiens Handlingar n.s. 44:555(5):84. (1916) Tuckerman: American Journal of Science, and Arts ser. 2, 6:228. (1848)
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