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Clasping Venus' Looking-glass (Triodanis perfoliata (L.) Nieuwl.)

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An annual native to North and South America; introduced onto several other continents. One of many small, inconspicuous plants that usually go unnoticed except when people see its colorful flowers.

The common name references two things: the fact that the leaves clasp the stem at the base, and the resemblance to the European species "Venus' Looking-glass" Legousia speculum-veneris, which is named for its conspicuously shiny seeds, a characteristic not as noticeable on this species.

Range - Expand

Native or Not Present

This tentative map is based on our own research. It may have limited data on Canada and/or Mexico, and there is some subjectivity in our assignment of plants as introduced vs. expanded. Read more in this blog post.


Prefers full sunlight and sandy or gravely soil, with mesic to dry conditions, but can tolerate partial sun in otherwise exposed conditions.

Found in sunny, sparsely vegetated open ground: grasslands with sandy or gravely soils, roadsides and railroads. In urban areas, barren vacant lots, cracks in sidewalk, and sunny areas up against buildings. Humans have created a lot of habitat for this species, but it is erratic and not usually abundant.

This is the most common and widespread of seven Triodanis species in North America. All are native. The European plant by a similar common name, Legousia speculum-veneris is slightly more distantly related, and has become established at a few isolated sites in Pennsylvania and California.

Numerous other plants of Campanulaceae, the bellflower family, also occur in its range, including both native and introduced species.

Triodanis perfoliata (Venus' Looking Glass) | Illinois Wildflowers (About This Site)

Triodanis perfoliata (Clasping Venus' Looking-glass) | USDA PLANTS Database (About This Site)

Triodanis perfoliata | Go Botany (About This Site)

Triodanis perfoliata | Biota of North America Project (BONAP) (About This Site)

Triodanis perfoliata | NatureServe Explorer (About This Site)

Triodanis perfoliata | Missouri Plants (About This Site)

Clasping Venus Looking-glass | Maryland Biodiversity Project (About This Site)

Triodanis perfoliata (Clasping-leaved Venus' Looking-glass) | Minnesota Wildflowers (About This Site)

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Photo © , CC BY-SA 4.0.