1. Prunella vulgaris L. (self-heal, heal-all)

Pl. 439 g–i; Map 1981

Plants perennial herbs, fibrous-rooted, occasionally with short rhizomes. Stems 10–50 cm long, erect or ascending to nearly prostrate, bluntly 4-angled (sometimes relatively weakly so), usually branched, glabrous or sparsely to moderately pubescent with short, ascending hairs or more or less spreading to somewhat curved, multicellular hairs, these sometimes only toward the stem tip or mostly along the angles and at the nodes. Leaves opposite and sometimes also basal, short- (toward the stem tip) to long- (toward the stem base) petiolate, the petioles often winged above the midpoint. Leaf blades 2–9 cm long, 0.7–4.0 cm wide, lanceolate to oblong-lanceolate, narrowly elliptic, ovate, or oblong-ovate, rounded, angled, or tapered at the base, angled or tapered to a bluntly or sharply pointed tip, the margins entire, shallowly wavy, or finely and sometimes irregularly toothed, the surfaces glabrous or sparsely short-hairy, the undersurface usually also with inconspicuous, sessile glands. Inflorescences terminal, dense spikes, more or less continuous, with (4)6 flowers per node, each node with a pair of leaflike bracts, these 5–15 mm long, 7–14 mm wide, depressed-ovate, abruptly short-tapered to a sharply pointed but not spinescent tip, the outer surface usually strongly purplish-tinged, the margins usually densely hairy, but not toothed or spinescent. Bractlets absent or minute, inconspicuous, and linear. Calyces zygomorphic, 6–10 mm long at flowering, 2-lipped, lacking a lateral projection, symmetric at the base, more or less cylindric to narrowly bell-shaped, the tube irregularly 10-nerved, hairy, often mainly along the nerves, glabrous in the mouth, the lips longer than the tube, the upper lip relatively broad and with 3, shallow, equal, triangular lobes at the tip, the lower lip narrower and deeply 2-lobed, the lobes narrowly triangular, the lobes all tapered to sharply pointed, soft or minutely spinescent tips, hairy along the margins, not or becoming only slightly enlarged and somewhat leathery at fruiting. Corollas 10–15(–19) mm long, zygomorphic, the lower lip with darker nerves or central spot, the outer surface glabrous or sparsely hairy, the tube funnelform, 2-lipped, the lips shorter than the tube, the upper lip entire or occasionally minutely notched, hooded, purplish blue to purple, lavender, or rarely white, often pale along the margin, the lower lip shorter than the upper lip, shallowly 3-lobed, spreading, white to pale lavender, usually with a darker line or markings on the inner surface, often somewhat irregular to shallowly fringed along the margins. Stamens 4, not or only slightly exserted (curved under the upper lip), the filaments (sometimes only the longer pair) more or less forked near the tip, only the lower forks bearing the anthers, the anthers small, the connective somewhat expanded, the pollen sacs 2, spreading, dark purple to bluish purple. Ovary deeply lobed, the style appearing nearly basal from a deep apical notch. Style not or only slightly exserted, with 2 slender branches at the tip. Fruits dry schizocarps, separating into usually 4 nutlets, these 1.6–2.0 mm long, ovoid to ellipsoid, the surface yellowish brown to brown with darker longitudinal lines that tend to converge at the ends, glabrous, smooth, shiny, the basal end with a small, pyramidal, white outgrowth (caruncle) . 2n=28, 32. May–September.

Scattered nearly throughout the state (nearly worldwide). Bottomland forests, mesic to dry upland forests, banks of streams and rivers, margins of ponds and sinkhole ponds, upland prairies, and tops of bluffs; also pastures, fencerows, old fields, ditches, railroads, roadsides, and disturbed areas.

As the vernacular name heal implies, this species has an extensive history of medicinal use for the treatment of most if not all ailments. Prunella vulgaris is a subcosmopolitan species within which numerous subspecies, varieties, and forms have been named. The plant has been transported between continents by humans, which has tended to confound attempts to create regionally based classifications to account for the morphological variation. The species deserves more detailed taxonomic studies. In North America, P. vulgaris can be divided into two principal varieties, one native and the other introduced from Europe. The taxonomic situation is complicated by the fact that both varieties apparently occur natively in portions of China (H. W. Li and Hedge, 1994). A. P. Nelson (1964), who studied plants from a mixed California population in the field and in common greenhouse culture concluded that the two varieties are genetically different, that they maintain themselves though high levels of self-pollination, but that limited hybridization gave rise to a small number of morphologically intermediate individuals.