Potamogeton richardsonii

(A. Bennett) Rydberg

Bulletin of the Torrey Botanical Club 32: 599. 1905.

Common names: Potamot de Richardson
Basionym: Potamogeton perfoliatus var. richardsonii A. Bennett J. Bot. 27: 25. 1889
Synonyms: Potamogeton perfoliatus subsp. richardsonii (A. Bennett) Hultén
Treatment appears in FNA Volume 22.

Rhizome present. Cauline stems terete, without spots, to 100 cm; nodal glands absent. Turions absent. Leaves submersed, ± spirally arranged, sessile, lax; stipules persistent, conspicuous, convolute, free from blade, white, not ligulate, 0.12–0.17 cm, fibrous, disintegrating to persistent fibers, even on proximal portion of stem, shredding at apex, apex obtuse; blade olive green, ovate-lanceolate to narrowly lanceolate, not arcuate, 1.6–13 cm × 5–28 mm, base rounded, without basal lobes, clasping, margins entire to crispate, apex not hoodlike, not splitting when pressed, acute to obtuse, lacunae absent; veins 3–35. Inflorescences emersed, unbranched; peduncles not dimorphic, terminal or axillary, erect to rarely recurved, clavate, 1.5–14.8 cm; spikes not dimorphic, cylindric, 13–37 mm. Fruits sessile, greenish brown, obovoid, turgid to concave, not or rarely abaxially keeled, not laterally keeled, 2.2–4.2 × 1.7–2.9 mm; beak erect, 0.4–0.7 mm; sides without basal tubercles; embryo with 1 full spiral. 2n = 52.

Phenology: Flowering summer–fall.
Habitat: Alkaline waters of lakes, streams, and rivers
Elevation: 0–3000 m


V22 326-distribution-map.jpg

Alta., B.C., Man., N.B., N.W.T., N.S., Ont., Que., Sask., Yukon, Alaska, Calif., Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mont., Nebr., Nev., N.H., N.Y., N.Dak., Ohio, Oreg., Pa., S.Dak., Utah, Vt., Wash., Wis., Wyo.


Potamogeton richardsonii is quite similar to P. perfoliatus. Specific characteristics to separate the two species are the shape of the leaf blade apex, acute in P. richardsonii and obtuse in P. perfoliatus, and the condition of the stipules, disintegrating between the veins leaving fibrous strands in P. richardsonii, and the entire stipule, including the veins, disintegrating in P. perfoliatus.

Two hybrids, Potamogeton gramineus × P. richardsonii (= P. × hagstroemii A. Bennett [as hagstromii]) and P. nodosus × P. richardsonii (= P. × rectifolius A. Bennett), have been described.

Selected References


Lower Taxa

... more about "Potamogeton richardsonii"
Robert R. Haynes +  and C. Barre Hellquist +
(A. Bennett) Rydberg +
Potamogeton perfoliatus var. richardsonii +
Potamot de Richardson +
Alta. +, B.C. +, Man. +, N.B. +, N.W.T. +, N.S. +, Ont. +, Que. +, Sask. +, Yukon +, Alaska +, Calif. +, Colo. +, Conn. +, Idaho +, Ill. +, Ind. +, Iowa +, Maine +, Mass. +, Mich. +, Minn. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.Y. +, N.Dak. +, Ohio +, Oreg. +, Pa. +, S.Dak. +, Utah +, Vt. +, Wash. +, Wis. +  and Wyo. +
0–3000 m +
Alkaline waters of lakes, streams, and rivers +
Flowering summer–fall. +
Bulletin of the Torrey Botanical Club +
Weedy +, Illustrated +  and Endemic +
Potamogeton perfoliatus subsp. richardsonii +
Potamogeton richardsonii +
Potamogeton +
species +