Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Potamogeton pusillus subsp. gemmiparus

Potamogeton pusillus subsp. pusillus
Photo is of parent taxon

potamot gemmipare
Photo is of parent taxon

potamot nain, small pondweed
Leaves

stipules convolute;

blade 1.1–6 cm × 0.2–0.7 mm, apex subulate, lacunae present or absent, 0–2 rows on each side of midrib;

veins 1.

stipules connate;

blade 1.4–6.5 cm × 0.5–1.9 mm, apex acute or rarely apiculate, rarely with bristle, lacunae present or absent, 0–2 rows each side of midrib;

veins 1–3.
Inflorescences

peduncles 1–3 per plant, cylindric;

spikes cylindric, continuous.

peduncles 1–3 per plant, filiform to cylindric;

spikes cylindric, interrupted.
Fruits

obovoid, sides centrally concave;

beak median.

obovoid, sides centrally concave;

beak toward adaxial edge, rarely median.
2n

= 26 (Eurasia).

Potamogeton pusillus subsp. gemmiparus

Potamogeton pusillus subsp. pusillus
Phenology Flowering and fruiting summer–fall. Flowering and fruiting spring–fall.
Habitat Acid waters of lakes and streams Streams, lakes, or marshes
Elevation 0–100 m (0–300 ft) 0–3300 m (0–10800 ft)
Distribution
from FNA
CT; MA; ME; NH; NH; VT; QC
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; YT; South America; Eurasia; Africa
Discussion

Potamogeton pusillus subsp. gemmiparus is an uncommon taxon that superficially resembles subsp. pusillus. It can be separated, however, by its continuous inflorescences, whereas those of subsp. pusillus are interrupted.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Potamogeton pusillus subsp. pusillus is nearly worldwide. When it is in fruit, the inflorescence is interrupted. That character combined with its narrow, linear, 1–3-veined leaves makes this taxon easily recognized. The nodal glands are green, essentially the color of the stems. Often appearing only as bumps on the stem at the nodes, they are difficult to see. Also, because the glands frequently occur at only a few nodes per plant, one can easily overlook them.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 22. FNA vol. 22.
Parent taxa Potamogetonaceae > Potamogeton > Potamogeton pusillus Potamogetonaceae > Potamogeton > Potamogeton pusillus
Sibling taxa
P. pusillus subsp. pusillus, P. pusillus subsp. tenuissimus
P. pusillus subsp. gemmiparus, P. pusillus subsp. tenuissimus
Synonyms P. pusillus var. gemmiparus, P. gemmiparus P. panormitanus, P. pusillus var. minor
Name authority (J. W. Robbins) R. R. Haynes & Hellquist: Novon 6: 370. (1996) unknown
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, OregonFlora

The species comparison tool is brought to you by:
Northwest Wildflowers