3. Verbena brasiliensis Vell. (Brazilian vervain)

Pl. 573 k, l; Map 2686

Plants annual (perennial farther south). Stems 60–150(–250) cm long, stiffly erect with ascending branches, strongly 4-angled, the angles and sometimes also the surfaces sparsely to moderately pubescent with nonglandular, strongly ascending hairs, usually strongly roughened to the touch. Leaves sessile or nearly so, the blades 2–10(–15) cm long, elliptic to elliptic-obovate, tapered to a slender, nonclasping base, rounded or angled to a bluntly or sharply pointed tip, the margins finely to coarsely toothed, often only above the midpoint, both surfaces moderately to densely pubescent with stiff, loosely ascending to more or less appressed, nonglandular, sometimes pustular-based hairs. Inflorescences solitary or in clusters of 3(5) spikes, noticeable as individual units, dense (the flowers strongly overlapping) but not appearing as headlike clusters, slender to moderately stout, 1–4 cm long, not elongating much with age. Bracts 2.5–4.0 mm long, usually slightly longer than the calyx, narrowly lanceolate to narrowly triangular. Calyces 2.0–3.5 mm long. Corollas 3–6 mm long, the outer surface densely hairy, narrowly trumpet-shaped, sometimes nearly tubular, purple to purplish blue, the tube slender, the limb 2–3 mm in diameter. Nutlets 1.2–1.8 mm long, oblong to elliptic-oblong in outline, the inner surface usually pale and with dense, minute papillae, the outer surface brown, with several longitudinal ridges, these with several cross-ridges toward the tip. 2n=28. May–October.

Introduced, known thus far only from the city of St. Louis (native of South America, introduced sporadically in the U.S., mostly in southeastern states; also Mexico, Caribbean Islands and in the Old World). Railroads.

This species was first reported for Missouri by Mühlenbach (1979) from his inventories of the St. Louis railyards. Moldenke (1982) reported another occurrence in Washington County without supplemental information or citation of a voucher specimen. No specimens could be located during the present study to support this claim.