Potamogeton ogdenii

Hellquist & R. L. Hilton

Systematic Botany 8: 88, figs. 1–3, plates 1–2, figs. 1–3. 1983.

Common names: Ogden's pondweed potamot d’Ogden
EndemicConservation concern
Treatment appears in FNA Volume 22.

Rhizomes absent. Cauline stems compressed-filiform, without spots, to 50 cm; glands green, golden brown to dark brown, 0.2–0.6 mm diam. Turions terminal or lateral, uncommon, 3.7–9.9 × 2.6–6 cm, soft to hard; leaves flattened with outer and inner leaves in same plane; outer leaves 1–2 per side, base not corrugate, apex apiculate; inner leaves undifferentiated or rolled into hardened, fusiform structure. Leaves submersed, ± spirally arranged, sessile, rigid; stipules persistent, inconspicuous, convolute, free from blade, brown or rarely white, not ligulate, 0.9–2.1 cm, slightly fibrous, partially shredding at tip, apex obtuse; blade somewhat reddish to olive-green, linear, not arcuate, 1.5–10 cm × 1.2–2.9 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, cuspidate to bristle-tipped, lacunae present or absent, in 0–3 rows each side of midvein; veins 3–9(–13). Inflorescences unbranched, emersed; peduncles not dimorphic, terminal or occasionally axillary, erect or rarely recurved, slightly clavate, 1–3 cm; spikes not dimorphic, cylindric, 5–11 mm. Fruits sessile, dark green, orbicular, turgid, abaxial keel obscure, lateral keels obscure or absent, 2.5–3 × 2.2–3 mm, lateral keels if present without points; beak erect, 0.5 mm; sides without basal tubercles; embryo with 1 full spiral. Chromosome number unknownnot available.


Phenology: Flowering mid summer–fall.
Habitat: Alkaline waters of ponds and lakes
Elevation: 100–300 m

Distribution

V22 57-distribution-map.jpg

Ont., Conn., Mass., N.Y., Vt.

Discussion

Potamogeton ogdenii is an extremely local species, probably known from fewer than a dozen localities. The species is herein reported for the first time from Canada, being known from that country by a single collection made in 1987.

Of conservation concern.

Selected References

None.

Lower Taxa

None.
... more about "Potamogeton ogdenii"
Robert R. Haynes +  and C. Barre Hellquist +
Hellquist & R. L. Hilton +
Ogden's pondweed +  and potamot d’Ogden +
Ont. +, Conn. +, Mass. +, N.Y. +  and Vt. +
100–300 m +
Alkaline waters of ponds and lakes +
Flowering mid summer–fall. +
Systematic Botany +
Endemic +  and Conservation concern +
Potamogeton ogdenii +
Potamogeton +
species +