Potamogeton diversifolius
Potamogeton floridanus
diverse-leaf pondweed, Rafinesque's pondweed, water-thread pondweed
Florida pondweed
present.
present.
compressed, without spots, 10–35 cm;
glands absent.
terete, without spots, ca. 50 cm.
absent.
unknown.
both submersed and floating or floating absent, ± spirally arranged.
submersed and floating, ± spirally arranged.
petiolate;
petioles continuous in color to apex, 0.7–0.8 cm;
blade adaxially light green, obovate to elliptic, 0.8–1.6 cm × 3–8.5 mm, base acute, apex round to acute;
veins 3–7.
petioles continuous in color to apex, 4–6.5 cm;
blade adaxially dark brown, elliptic, 4.5–6.6 cm × 7–12 mm;
base acute, apex acute;
veins 7–11.
sessile, lax;
stipules persistent to deliquescent, inconspicuous, convolute, adnate to blade ½ stipule length, light brown to red-brown, ligulate, 1.5–2.3 cm, not fibrous, not shredding at tip, apex obtuse;
blade red-brown to light green, linear, often arcuate, 1–1.3 cm × 0.1 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute, lacunae present, 1–2 rows each side midrib;
veins 1.
sessile, lax;
stipules persistent, inconspicuous, convolute, free from blade, whitish, not ligulate, 2.5–4 cm, delicately fibrous, eventually shredding, apex acute;
blade dark green to olive-green, narrowly linear, not arcuate, 15–20 cm × 0.7 mm, base attenuate, not clasping, not lobed, margins entire, not crispate, apex not hoodlike, acute, lacunae absent;
veins 1.
unbranched;
peduncles dimorphic, submersed axillary, recurved, clavate, 3–5 mm, emersed axillary or terminal, erect to slightly recurved, clavate, 6–15 mm;
spikes dimorphic, submersed capitate, 2–3 mm, emersed cylindric, 5–9.7 mm.
unknown.
sessile, greenish brown, orbicular, compressed, abaxially winged, laterally winged, 1–1.5 × 0.9–2 mm, lateral wings with sharp points;
beak present, erect, 0.1 mm;
sides without basal tubercles;
embryo with more than 1 full spiral.
unknown.
Potamogeton diversifolius
Potamogeton floridanus
Potamogeton diversfolius is very likely the most common species of Potamogeton the genus in the southeastern United States. It has been separated into two species, P. diversifolius in the strict sense and P. capillaceus (M. L. Fernald 1932). The species has also been divided into two varieties, var. diversifolius and var. trichophyllous Morong (D. O S. Correll and M. C. Johnston 1970) . Potamogeton diversifolius var. trichophyllous actually is misapplied, as the name really refers to the more northern P. bicupulatus Fernald. We are following E. J. Klekowski Jr. and E. O. Beal (1965) in accepting only one taxon, as we have studied the species over much of its range and reached similar conclusions.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Potamogeton floridanus is an extremely localized species of the panhandle of Florida. No one has treated the species recently (E. C. Ogden 1943; R. R. Haynes 1978). Four populations of the taxon were reported from Santa Rosa County, Florida (G. S. Wilhelm and R. H. Mohlenbrock 1986). Those populations clearly match the protologue and the original collections. One population has recently been found fertile (J. R. Burckhalter, pers. comm.), but we have not examined the specimens. Because the taxon persists and has a vegetative morphology unlike any other pondweed, we believe it must be recognized. Until a better understanding of the taxon is developed, we prefer to recognize it at the specific level.
Of conservation concern.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
CA, 
OR - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
