Small Venus' looking-glass is a native annual in the Campanulaceae (bellflower) family. Its common name is derived from an early botanical description of a similar appearing plant native to Europe. That was the Legousia speculum, which had seeds that were said to be as shiny as a looking glass. The seeds of the Triodanis perfoliate subsp. biflora are too small to detect the shiny appearance. It is also said that the flattened seeds resemble a hand mirror, thus the common name. It is found all over the southern half of the U.S.A., Mexico and parts of South America most often in disturbed sites such as prairies, roadsides, rocky outcrops, gravel pits, open woods and grassy slopes. It prefers poor, dry, sandy or gravelly soil where there is not much competition with other plants. After blooming, it will fade away. Typical heights are up to 12", however, it can reach heights of up to 30". Although the leaves are alternate, a pair of opposite leaves appear at the top of the stem. These leaves are somewhat larger than the lower leaves. They are cordate and have wavy margins. The stems and leaves each have a milky sap. It has showy five petaled flowers that range in color from blue-violet to pink-purple to lavender. The center holds a white style. The sepals, which form a cup for the flower, can have narrow triangular lobes that are shorter than the petals and form a tapered or sharp pointed tip. The lower flowers are smaller than the upper flowers and do not open. Considered to be cleistogamous, whose lower, non-opening flowers are an automatic self pollinators. Small bees such as the Plasterer bee, Little Carpenter bee as well as bumblebees, flies, small butterflies and skippers frequent this plant. Insects, Diseases, and Other Plant Problems: Can become weedy. Deadheading can control its self-seeding.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Sand; Shallow Rocky
Soil pH
Neutral (6.0-8.0)
Soil drainage
Good Drainage | Occasionally Dry
Available space
12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Growth rate
Medium
Maintenance
Medium
Canopy layer
4 - Herbaceous
Form & Appearance
Habit / form
Erect
Texture
Medium
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Cordate; Ovate; Reniform
Leaf margin
Entire; Serrate
Leaf size
< 1 inch long, < 1 inch wide
Hairs present
Yes
Leaf detail
Alternate, simple, sessile, light green leaves are broadly egg-shaped to heart or kidney-shaped, rounded to somewhat pointed at the tip. Margins are serrate to entire. They are up to 1 inch long and nearly as wide. The leaves are stalkless and clasp the stem at the base. Stiff hairs may cover the surface except for the upper leaves, which may be hairless.
Flower color
Pink; Purple/Lavender
Flower value
Showy
Flower form
Solitary
Flower shape
Bell; Star
Flower size
< 1 inch
Flower detail
5-petaled purple-violet to pink solitary flowers with center disc flowers. They are bell or star shape on upper stems. Flowers on the lowest part of the stem are small, self-fertile, without petals and do not open. The upper flowers are showy.
Bloom time
Spring; Summer
Fruit color
Brown/Copper
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruits take the for of a 2-3 parted oval capsule with persistent calyx lobes spreading out at the tip. As they mature, they split from top to bottom, releasing many reddish-brown seeds.
Stem color
Green
Stem detail
The light green, single, erect stems are angled, stiffly hairy (white) along the angles, unbranched or branched near the base. They tend to be weak.
Wildlife & Ecology
Native status
Native
Origin
Southern USA from west coast to east, Mexico, South America
Distribution
AL, AR, AZ, CA, FL, GA, HI, IL, KS, KY, LA, MO, MS, NC, NE, NM, NY, OK, OR, PA, SC, TN, TX, VA
Wildlife value
Small bees are attracted. The Plasterer Bee prefers the nectar.