6. Scutellaria nervosa Pursh (veiny skullcap)

S. nervosa var. calvifolia Fernald

Pl. 443 a, b; Map 1997

Plants with slender, inconspicuous rhizomes. Stems 15–50(–60) cm long, erect or ascending, often from a spreading base, unbranched or few-branched, glabrous or sparsely pubescent on the angles and nodes with short, upward-curved, nonglandular hairs. Leaves sessile or the lower leaves with petioles to 4 mm long. Leaf blades 1–3 cm long, mostly 1–2 times as long as wide, narrowly to broadly ovate, rounded to truncate or shallowly cordate at the base or occasionally broadly angled, rounded or bluntly to sharply pointed at the tip, the margins of at least the larger leaves with broadly spaced, shallow, usually rounded teeth, the surfaces glabrous or sparsely pubescent with short, more or less spreading, nonglandular hairs, the undersurface usually also with sessile glands. Inflorescences of axillary flowers, these 2 per node, solitary in the axils of the upper foliage leaves. Calyces 2.5–3.5 mm long, becoming closed and enlarged to 5–7 mm at fruiting, the outer surface sparsely to moderately pubescent along the nerves with short, curved, nonglandular hairs. Corollas 8–11 mm long, minutely nonglandular-hairy on the outer surface, pale blue or white, the lower lip usually finely spotted with white or reddish purple toward the base, the tube not or only slightly S-shaped (relatively straight above the calyx, oblique at or above the throat), the lateral lobes not well-developed, ascending, the lower lip broadly fan-shaped, irregular or faintly scalloped along the margin. Nutlets 1–4 per calyx, 1.0–1.2 mm long, more or less globose, the surface dark brown to black, densely warty or with rounded tubercles, interrupted by a broad, smooth, transverse band. 2n=20. May–July.

Scattered, mostly in the eastern half of the state (eastern U.S. west to Iowa and Louisiana; Canada). Banks of streams, rivers, and spring branches, margins of ponds and lakes, bottomland forests, bases of bluffs, sloughs, and swamps.

Steyermark (1963) and some other authors have attempted to separate this species into two varieties, based on whether the upper leaf surface is glabrous (var. calvifolia) or sparsely hairy (var. nervosa). There is no discontinuity for this character, and nearly glabrous-leaved plants are commonly encountered. Rare plants with white corollas have been called f. alba Steyerm.