Veronica triphyllos L.
Family - Plantaginaceae
Stem - Usually strongly erect, especially later in season, to 17 cm, pubescent with spreading glandular hairs.
Leaves - Opposite (leaflike bracts of the inflorescence usually alternate). Leaves sessile, simple, to 1.5 cm long, broadly ovate, rounded to truncate at base, deeply 3-7 palmately lobed, surfaces pubescent with short, glandular hairs.
Inflorescence - Terminal spikelike raceme, elongating with age, often nearly the entire length of the plant. Axis visible between flowers. Bracts alternate, similar to leaves, gradually reduced toward tip. Flowers on stalks 2-5 mm long, elongating in fruit.
Flowers - Calyces 3-4 mm long, elongating in fruit, deeply 4-lobed, the upper 2 lobes shorter than the lower 2 lobes, the lobes pubescent with spreading, glandular hairs. Corollas 3.0-4.5 mm wide, blue with darker veins, the throat usually light green. Stamens 2. Style 1, 1.2-1.6 mm long at fruiting.
Fruits - 4.2-5.5 mm long, usually slightly longer than wide, heart-shaped in profile, flattened, the notch relatively deep (0.8-1.1 mm), the surfaces glandular-hairy. Seeds mostly 6-12 per locule, 1.5-2.0 mm long, cup-shaped, the convex surface appearing cross-wrinkled, brown.
Flowering - April - June.
Habitat - Agricultural fields, disturbed areas.
Origin - Native to Eurasia.
Other info. - This small speedwell was first reported for Missouri in 1992. It is still uncommon in the state, though it can form huge populations in crop fields where it is found, and is probably spread by agricultural equipment. It blooms in the spring, typically completing its life cycle and disappearing before the crop is sown. The heart-shaped fruits are diagnostic for the genus. Relative to other Veronicas, it tends to have flowers which are a deeper and more uniform blue, and the deeply lobed leaves and bracts are also distinctive.
Photographs taken near Labadie, Franklin County, MO, 4-17-2014 and 3-30-2015 (SRTurner).