Triodanis leptocarpa (Nutt.) Nieuwl.

Slender-Leaved Venus' Looking Glass

Triodanis leptocarpa plant

Family - Campanulaceae

Stems - To 70cm, herbaceous, simple, from taproot, angular, strigose on angles, to 3mm thick, erect, with milky sap.

Leaves - Alternate, linear to (ob)lanceolate, sessile to short-petiolate, entire to crenate, to 25mm long, 5mm broad, strigose below, typically glabrous above.

Triodanis leptocarpa leaves

Inflorescence - Axillary clusters of typically 2-3 chasmogamous flowers but sometimes single, lower flowers cleistogamous.

Upper flowers - Chasmogamous. Corolla blue-purple, 5-lobed, -2cm broad, glabrous. Lobes to 8mm long, 3-4mm broad, lance-ovate. Tube to 1.5cm long. Stamens 5, adnate at base of corolla tube, alternating with lobes. Filaments purple, 1.5mm long. Anthers yellow, filiform, 2-3mm long, connate around style and stigma, curling when mature and dehiscing. Style 1, 7mm long, glabrous, white below, purple above. Stigma 2-lobed. Ovary inferior. Calyx tube to 1.5cm long, 1.8mm in diameter, 5-lobed, scabrous. Lobes spreading to recurved, linear, to 8mm long, strigose. Fruit many seeded.

Lower flowers - Cleistogamous. Calyx tube to 1.5cm long, lobes to 6mm long, spreading or slightly recurving.

Triodanis leptocarpa calyxCalyx.

Triodanis leptocarpa flowerFlower close-up.

Triodanis leptocarpa fruitDeveloping fruit.

Flowering - May - June.

Habitat - Disturbed sites, waste ground, pastures, prairies, roadsides, railroads.

Origin - Native to U.S.

Other info. - The typical leaf morphology is linear. This species is common in drier areas of the habitats mentioned above. The fruits are dimorphic with the cleistogamous flowers producing a slightly larger capsule.
A formerly used name was Specularia leptocarpa

Photographs taken at Dave Rock Conservation Area, St. Clair County, MO., 5-12-00 & 6-7-03 (DETenaglia); also near Cedar Fourche, AR, 5-5-2015 (SRTurner).