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little aguja pondweed

Ogden's pondweed, potamot d'Ogden

Rhizomes

absent.

absent.

Cauline stems

terete to slightly compressed, without spots, to 57 cm;

glands white to gold, 0.2–0.3 mm diam.

compressed-filiform, without spots, to 50 cm;

glands green, golden brown to dark brown, 0.2–0.6 mm diam.

Turions

unknown.

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, 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).

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, 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, terminal or occasionally axillary, erect or rarely recurved, slightly clavate, 1–3 cm;

spikes not dimorphic, cylindric, 5–11 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 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.

Potamogeton clystocarpus

Potamogeton ogdenii

Phenology Flowering and fruiting spring–summer. Flowering mid summer–fall.
Habitat Small streams Alkaline waters of ponds and lakes
Elevation ca. 1800 m (ca. 5900 ft) 100–300 m (300–1000 ft)
Distribution
from FNA
TX
[BONAP county map]
from FNA
CT; MA; NY; VT; ON
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.)

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.

(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. 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. subsibiricus, 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. perfoliatus, P. praelongus, P. pulcher, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. strictifolius, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
Name authority Fernald: Memoirs of the american academy of arts and science n.s. 17:79, plates 15, 30, fig. 5. (1932) Hellquist & R. L. Hilton: Systematic Botany 8: 88, figs. 1–3, plates 1–2, figs. 1–3. (1983)
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