Potamogeton tennesseensis

Fernald

Rhodora 38: 167, plate 412. 1936.

Common names: Tennessee pondweed
EndemicConservation concern
Treatment appears in FNA Volume 22.

Rhizomes present. Cauline stems terete, without spots, 10–35 cm; glands absent. Turions absent. Leaves both submersed and floating or floating absent, spirally arranged. Submersed leaves sessile, lax; stipules persistent, inconspicuous, convolute, adnate to blade for ¼ or less stipule length, light-brown to dark green, ligulate, 0.5–1.5 cm, not fibrous, not shredding at tip, apex acute; blade redbrown to dark green, linear-filiform, not arcuate, 2.5–10.5 cm × 0.2–1 (–2) mm, base slightly tapering, not clasping, without basal lobes, margins entire, not crispate, apex not hoodlike, long tapering, lacunae abundant, broad, filling area between margin and midvein; veins 1–3. Floating leaves petiolate; petioles continuous in color to apex, 2.5–6 cm; blade greenish brown adaxially, lance-oblong, 2–4 (–5.5) cm × 5–13 mm, base acute, apex acute; veins 9–23. Inflorescences unbranched, emersed; peduncle not dimorphic, axillary, ascending, cylindric, 3–8 cm; spikes not dimorphic, cylindric, 10–22 mm. Fruits sessile, greenish brown, quadrate-orbicular, slightly compressed, abaxially keeled, laterally ridged, 2.5–3 × 2–2.5 mm; lateral ridges without points; beak present, erect, 0.5 mm; sides without basal tubercles; embryo with less than 1 full spiral.


Phenology: Flowering mid spring–fall.
Habitat: Slow- to fast-moving streams and rivers
Elevation: 200–1000 m

Distribution

V22 521-distribution-map.jpg

Ky., Md., N.C., Ohio, Pa., Tenn., Va., W.Va.

Discussion

No specimens have been seen from Maryland although the species is to be expected there.

Of conservation concern.

Selected References

None.

Lower Taxa

None.

"shortened" is not a number."not elongating" is not a number."light-brown" is not a number. "dark green" is not a number.

... more about "Potamogeton tennesseensis"
acute +, tapering +, not hoodlike +  and not acute +
Robert R. Haynes +  and C. Barre Hellquist +
Fernald +
acute +  and tapering +
0.5 cm5 mm <br />0.005 m <br /> (?) +
4 cm40 mm <br />0.04 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
greenish brown +, redbrown +  and dark green +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
lance-oblong;linear-filiform +
0.5 cm5 mm <br />0.005 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
10 cm100 mm <br />0.1 m <br /> (35 cm350 mm <br />0.35 m <br />) +
Tennessee pondweed +
Ky. +, Md. +, N.C. +, Ohio +, Pa. +, Tenn. +, Va. +  and W.Va. +
200–1000 m +
greenish brown +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
ridged +, keeled +, compressed +  and quadrate-orbicular +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Slow- to fast-moving streams and rivers +
axillary +  and terminal +
cylindric +  and capitate +
petiolate +  and sessile +
submersed +
not crispate +
orthotropous +
not pedunculate +
emersed +  and submersed +
cylindric +  and capitate +
not spiraling +
not dimorphic +
cylindric +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (6 cm60 mm <br />0.06 m <br />) +
Flowering mid spring–fall. +
short-stipitate +  and stipitate +
4 +  and 1 +
auriculate +  and not auriculate +
not persisting +
Endemic +  and Conservation concern +
not dimorphic +
emersed +  and submersed +
cylindric +
1 cm10 mm <br />0.01 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
epitepalous +
compressed;terete +
inconspicuous +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
not fibrous +
Potamogeton tennesseensis +
Potamogeton +
species +
9 (?) +  and 23 (?) +
caulescent +, not rhizomatous +  and rhizomatous +
annual +  and perennial +