4. Verbena hastata L. (blue vervain)
Pl. 574 j–l; Map
2687
Plants
perennial. Stems 40–150(–220) cm long, erect or strongly ascending, moderately
to strongly 4-angled, moderately to densely pubescent with nonglandular,
somewhat curved, loosely ascending to appressed, often pustular-based hairs.
Leaves moderately petiolate, the petioles mostly 10–25 mm long, usually winged
toward the tip, the blades 4–20 cm long, at least those of the largest leaves
15–45 mm wide, lanceolate to oblong-lanceolate or narrowly ovate, rounded,
angled, or short-tapered to a nonclasping base, tapered to a sharply pointed
tip, unlobed or the larger leaves with a pair of spreading basal lobes, the
margins relatively coarsely and doubly toothed, both surfaces glabrous or
sparsely to moderately, but inconspicuously pubescent with short, loosely
appressed, nonglandular, occasionally pustular-based hairs (not appearing
grayish), sometimes roughened to the touch. Inflorescences usually panicles of
5 to numerous spikes, these 2–20 cm long, moderately dense (the flowers strongly
overlapping except sometimes the lowermost ones), appearing stout when young
but relatively slender at maturity, elongating greatly with age. Bracts 2.0–2.5
mm long, slightly shorter than the calyx, narrowly lanceolate. Calyces 2.3–3.0
mm long. Corollas 6–10 mm long, the outer surface sparsely to moderately hairy
near the tip of the tube, funnelform, purple to purplish blue (rarely white or
pink), the tube slightly broadened toward the tip, the limb 3.0–4.5 mm in
diameter. Nutlets 1.5–2.0 mm long, narrowly oblong to narrowly oblong-elliptic
in outline, the inner surface usually slightly pale and with sparse to
moderate, minute, appressed hairs, the outer surface reddish brown, smooth or
with several faint longitudinal ridges, these sometimes with a few, faint
cross-ridges toward the tip. 2n=14. June–October.
Scattered nearly
throughout the state, but less common in the Ozark Division than elsewhere
(throughout the U.S.; Canada). Banks of streams and rivers, margins of ponds,
sloughs, and lakes, bottomland prairies, fens, bottomland forests, mesic upland
forests, and ledges of bluffs; also fencerows, margins of crop fields, fallow
fields, ditches, railroads, roadsides, and open, disturbed areas.
Plants with the
pubescence tending to be stiffer and the stems and leaves thus more roughened
to the touch have been called var. scabra Moldenke, but these intergrade
fully with plants having somewhat softer pubescence. Rare plants with white
corollas have been called f. albiflora Moldenke, and plants with pink
corollas have been called f. rosea C.I. Cheney.