Potamogeton clystocarpus |
Potamogeton oblongus |
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little aguja pondweed |
cinnamonspot pondweed, potamot oblong |
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Cauline stems | terete to slightly compressed, without spots, to 57 cm; glands white to gold, 0.2–0.3 mm diam. |
terete, without spots, 5–30 cm; nodal glands absent. |
Turions | unknown. |
absent. |
Leaves | submersed, ± spirally arranged, sessile, delicate; stipules persistent, inconspicuous, convolute, free from blade, brown, not ligulate, to 0.62 cm, not fibrous, not shredding at tip, apex obtuse; blade green, linear, not arcuate, 3.2–7.8 cm × 0.7–1.7 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute, lacunae rarely absent, in 0–4 rows each side of midrib; veins 3(–5). |
both submersed and floating or only submersed, ± spirally arranged. |
Floating leaves | petioles continuous in color to apex, 1–17 cm; blade adaxially reddish brown, ovate, 3–8(–10) cm × 10–46 mm, base rounded or slightly cordate, apex obtuse, acute, or somewhat apiculate; veins (11–)15–19(–21). |
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Submersed leaves | petiolate, lax; stipules persistent, conspicuous, convolute, free from blade, greenish, not ligulate, to 3 cm, not fibrous, not shredding at tip, apex acute; petioles 1–3(–8) cm; blade dark green, lanceolate to occasionally ovate, occasionally arcuate, 3–13 cm × 4–15(–44) mm, base acute, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute, lacunae in 2–4 rows each side of midvein; veins 7–11. |
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Inflorescences | unbranched, emersed; peduncles not dimorphic, axillary or terminal, erect, cylindric, 3.2–4.8 cm; spike not dimorphic, capitate to cylindric, 5.5–7.5 mm. |
unbranched, emersed; peduncles not dimorphic, erect to slightly recurved, cylindric, 4–12 cm; spikes not dimorphic, cylindric, 20–40 mm. |
Fruits | sessile, brown to yellow-green, obovoid, compressed, abaxially and laterally keeled, 2–2.2 × 1.7–1.8 mm, lateral keels without points; beak erect, 0.5–0.6 mm; sides with 1–3 tubercules near base; embryo with 1 full spiral. |
sessile, dark reddish brown, obovoid to orbicularoid, compressed, not abaxially or laterally keeled, (1.6–)2–2.5 × (1.2–)1.5–2.1 mm; beak minute or obsolete, recurved; sides without basal tubercles; embryo with 1 full spiral. |
Rhizome(s) | absent. |
present. |
2n | = 26. |
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Potamogeton clystocarpus |
Potamogeton oblongus |
|
Phenology | Flowering and fruiting spring–summer. | Flowering July–August. |
Habitat | Small streams | Acid to neutral waters of ponds, lakes, and occasionally streams |
Elevation | ca. 1800 m (ca. 5900 ft) | 10–100 m (0–300 ft) |
Distribution |
TX |
NF; NS; SPM; Europe; n Africa; Atlantic Islands (Azores) [Introduced in North America] |
Discussion | Potamogeton clystocarpus is an extremely limited species known from only one canyon in west Texas. Of conservation concern. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Fernald: Memoirs of the american academy of arts and science n.s. 17:79, plates 15, 30, fig. 5. (1932) | Viviani: Annali di Botanica 1(2): 102. (1802) |
Web links |