Bacopa rotundifolia

(Michaux) Wettstein in H. G. A. Engler and K. Prantl

Nat. Pflanzenfam. 67[IV,3b]: 76. 1891

Common names: Round leaf water-hyssop
WeedySelected by author to be illustratedEndemic
Basionyms: Monniera rotundifolia Michaux Fl. Bor.-Amer. 2: 22. 1803
Synonyms: Bacopa nobsiana H. Mason B. simulans Fernald Bramia rotundifolia (Michaux) Britton Macuillamia rotundifolia (Michaux) Rafinesque
Treatment appears in FNA Volume 17. Treatment on page 261. Mentioned on page 260, 262, 263.
Click plate for higher resolution version.
Annuals [perennials]. Stems prostrate, 15–60 cm, hairy, sometimes sparsely so, glabrescent. Leaves hairy; blade base broadly cuneate, margins entire, apex ± rounded. Pedicels 9–15 mm. Flowers: sepals 5, ovate to oblong, calyx bilaterally symmetric; corolla white with yellow throat, 5–10 mm; stamens 2–4, equal. 2n = 56.

Phenology: Flowering May–Nov.
Habitat: In water or on mud in lakes, ponds, pools, in and around marshes and ditches, ephemeral pools on rock outcrops.
Elevation: 0–2300 m.


Alta., Sask., Ala., Ariz., Ark., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Md., Minn., Miss., Mo., Mont., Nebr., N.Mex., N.C., N.Dak., Okla., S.Dak., Tenn., Tex., Va., Wis., Wyo., introduced in Europe (Greece, Spain).


Bacopa rotundifolia is the most widespread member of the genus in the United States; it is invasive in rice fields.



Lower Taxa

No lower taxa listed.