2. Veronica anagallis-aquatica L. (water speedwell)

Pl. 490 j, k; Map 2233

Plants perennial, with rhizomes. Stems 10–60(–100) cm long, mostly strongly ascending to erect (occasionally plants flattened by flooding may have a more spreading growth form), glabrous or sparsely to moderately pubescent with minute, gland-tipped hairs toward the tip (and along the inflorescence axis). At least the upper and median leaves sessile, the lower leaves sometimes short-petiolate (vegetative, late-season stems with mostly short-petiolate leaves are sometimes produced). Leaf blades 1.5–8.0 cm long, mostly 1.5–3.0 times as long as wide, broadly lanceolate to ovate or occasionally oblong-ovate, broadest at or more commonly below the midpoint, sharply pointed at the tip (sometimes rounded or bluntly pointed on vegetative, late-season stems), rounded to truncate or shallowly cordate at the base, those of the sessile leaves more or less clasping the stems, the margins unlobed, flat, mostly subentire, usually with at least a few, widely spaced, minute teeth (occasionally the teeth more numerous), the surfaces glabrous or the undersurface inconspicuously glandular-hairy toward the base of the midvein. Inflorescences axillary racemes, these usually in opposite pairs at the stem nodes (1 per leaf), open at maturity, with (15–)25–60 flowers, the bracts 1.5–4.0 mm long, much smaller than the foliage leaves, linear to narrowly lanceolate. Flower stalks 2.5–5.0 mm long at flowering (to 8 mm long at fruiting), ascending or curved upward at flowering and fruiting. Calyces 3.0–5.5 mm long, the lobes unequal or slightly unequal, the upper 2 lobes then slightly shorter than the lower 2 lobes, deeply 4-lobed, the lobes lanceolate to broadly lanceolate, glabrous or minutely glandular-hairy toward the base. Corollas 5–10 mm wide, pale blue to light blue, pale purple, or light bluish purple with darker veins, the throat white or sometimes pale greenish-tinged at the base, the lobes loosely cupped upward. Style 1.5–3.0 mm long at fruiting. Fruits 2.5–4.0 mm long, mostly slightly longer than wide, broadly obovate to more or less circular in profile, somewhat turgid, the notch very shallow, the surfaces and margins glabrous or a few minute glandular hairs present along the margins, usually dehiscing both along and between the sutures into 4 valves. Seeds numerous, 0.3–0.5 mm long, strongly flattened on one side and somewhat convex on the other, the surfaces appearing smooth or slightly pebbled, light brown to brown. 2n=36. April–September.

Introduced, uncommon to scattered in the Ozark Division, north locally to a few counties along the Missouri River (native of Europe, Asia; introduced nearly throughout the U.S., Canada). Banks of streams, rivers, and spring branches, margins of lakes and sloughs, moist bases of bluffs, and disturbed wetlands; often emergent aquatics.

This taxon was first reported from Missouri by Nightingale and Olson (1984), but previously misdetermined herbarium specimens exist dating back to the 1930s. R. E. Brooks (1976), Gleason and Cronquist (1991), and others have noted the existence of sterile putative hybrids between V. anagallis-aquatica and the native V. catenata, but although these are to be expected in Missouri they have not yet been documented in the state. The two species are closely related members of a circumboreal complex and are separable by characters in the key above.