Figwort family (Scrophulariaceae)
Description: This introduced annual wildflower is 2-8" tall. It often branches near the base, but its stems are unbranched above. The slender stems are light green and hairy. The lower leaves are up to 3/8" long and across; they are yellowish green to green, hairy, oval-orbicular, crenate along their margins, and opposite. The petioles of the lower leaves are very short (about 1/8" long). As a plant matures, there is a tendency for the lower leaves to turn brown and wither away. The middle to upper leaves, where the flowers develop, are up to ¼" long, linear-oblong to lanceolate in shape, smooth or slightly crenate along their margins, sessile or nearly so, and alternate. Like the lower leaves, they are yellowish green to green and hairy. Solitary flowers develop from the axils of the middle to upper alternate leaves. Each flower is 1/8" across, consisting of a blue-violet to blue corolla with 4 petal-like lobes, 4 hairy green sepals, 2 stamens with white anthers, and a pistil with a single style. The corolla usually has a few faint veins originating from the center of the flower. The sepals are lanceolate-oblong and somewhat longer than the corolla. The tiny flowers bloom near the apex of the stems from mid-spring to mid-summer for 1-3 months. Each flower is replaced by an obcordate (heart-shaped) seed capsule. Individual seed capsules are 1/8" long, 1/8" across, somewhat flattened, and ciliate. Both the flowers and seed capsules are nearly sessile. Each seed capsule is 2-celled and contains many tiny seeds. The root system consists of a slender much-branched taproot. This wildflower reproduces by reseeding itself and it occasionally forms colonies.
Cultivation: The preference is full sun, mesic to dry-mesic conditions, and poor soil where there is reduced competition from other plants. The soil can contain sand, rocky material, loam, or clay.
Range & Habitat: Corn Speedwell is quite common and it can be found in every county of Illinois (see Distribution Map). This little weed was introduced accidentally from Europe. Habitats include scrubby savannas with sparse ground vegetation, rocky glades, fields, lawns and gardens, grassy areas along roads, and barren waste ground. Highly disturbed areas are preferred.
Faunal Associations: Small bees and Syrphid flies suck nectar from the flowers. Charles Robertson observed the Syrphid fly Toxomerus marginatus, and the Halictid bees Augochlorella aurata and Lasioglossum versatus visiting the flowers. However, floral visitors are uncommon and the flowers are capable of self-fertilization. The stink bug Cosmopepla lintneriana has been observed to suck juices from the foliage of Corn Speedwell (as well as many other plants).
Photographic Location: A lawn in Urbana, Illinois.
Comments: Corn Speedwell is one of several annual Veronica spp. (Speedwell species) that have been introduced from Europe. They are usually very weedy species. Because Corn Speedwell is small and not very showy, it is easy to overlook. The flowers are a lovely shade of blue-violet or blue, but they are very small in size and short-lived. Corn Speedwell can be distinguished from other similar species by its nearly sessile flowers and seed capsules, and the narrow alternate leaves (or leafy bracts) along the upper two-thirds of its stems. Its flowers are usually a deeper shade of blue than those of similar species. Another common name of Veronica arvensis is Field Speedwell.