1. Pedicularis canadensis L. (common lousewort, wood betony)

P. canadensis var. dobbsii Fernald

Pl. 472 a, b; Map 2164

Plants often colonial, with short rhizomes or stolons. Stems 10–30(–40) cm long, sparsely hairy toward the base, densely hairy or appearing woolly toward the tip and inflorescence axis. Basal leaves well-developed at flowering, long-petiolate. Stem leaves mostly alternate. Lower stem leaves long-petiolate. Leaf blades 2–9(–15) cm long, lanceolate to narrowly oblong-elliptic or occasionally oblanceolate, moderately to deeply lobed, those of the larger leaves lobed more than halfway to the midvein, the lobes finely toothed or scalloped to lobed again, usually with a narrow, thickened pale band along the margins, the surfaces sparsely hairy to nearly glabrous. Inflorescences terminal spikes or spikelike racemes, the flower stalks absent or to 3 mm long, relatively short and dense when the first flowers open, continuing to elongate and appearing less dense as the fruits develop. Calyces 7–9 mm long, strongly oblique, the tube with a pair of shallow, rounded teeth at the tip of the upper side (sometimes appearing merely shallowly notched), the lower side deeply notched or divided. Corollas 18–25 mm long, yellow or variously tinged with pink, red, or purple, rarely white, the upper lip 11–15 mm long, sometimes completely purple to dark purple, narrowed to a more or less truncate tip, but with a pair of short, slender, toothlike lobes just below the tip, the lower lip 7–10 mm long, the lobes spreading, the central lobe shorter and more sharply pointed than the lateral ones. Fruits 10–17 mm long. Seeds 1.6–2.2 mm long, more or less oblong-ellipsoid, not flattened, with a short, sharp point at the tip, truncate to concave at the base, unwinged, the surface with a fine but noticeable network of ridges, brown. 2n=16. April–May.

Scattered nearly throughout the state, less abundantly north of the Missouri River (eastern U.S. west to North Dakota and Texas; Canada). Glades, upland prairies, ledges and tops of bluffs, savannas, openings of mesic to dry upland forests, and less commonly banks of streams and rivers and openings of bottomland forests; also old fields, pastures, and roadsides.

Viewed from above, the inflorescences of this species often appear similar to pinwheels, with the flowers strongly spiraled. Flower color can vary greatly within populations. Rare plants with the corollas white or mostly white have been called f. albescens Steyerm. Steyermark (1963) noted anecdotal reports that P. canadensis is toxic to sheep.