Cycl. 26: Pedicularis no. 4. 1813.
Plants 7–65 cm. Leaves: basal 0–2, blade elliptic, 3–7 x 2–5 mm, 1-pinnatifid or 2-pinnatifid, margins of adjacent lobes nonoverlapping or slightly overlapping distally, dentate, surfaces glabrous; cauline 0–12, blade lanceolate or elliptic to deltate, 5–50 x 3–20 mm, 1-pinnatifid or 2-pinnatifid, margins of adjacent lobes nonoverlapping or slightly overlapping distally, serrate, surfaces glabrous. Racemes simple or paniculate, 1–4, exceeding basal leaves, each 3–12-flowered; bracts deltate to trullate, 5–30 x 3–15 mm, 1-pinnatifid or 2-pinnatifid, margins serrate, surfaces glabrous or slightly arachnoid. Pedicels 1–2.5 mm. Flowers: calyx 5.5–8 mm, glabrous, lobes 2 (–4), deltate, 2–3.5 mm, apex pinnatifid, sometimes 2-fid into triangular lobes, entire, glabrous; corolla 8–16 mm, tube light pink to purple, 5–11 mm; galea purple, 3–6 mm, beakless, margins 1-toothed medially, entire distally, apex arching slightly over abaxial lip; abaxial lip pink to purple, sometimes purple-spotted, 2–5 mm.
Phenology: Flowering Jun–Aug.
Habitat: Muskegs, boggy flood plains, gravel stream bars, moist meadows, sedge meadows, fens, bogs, black spruce-tamarack wetlands.
Elevation: 0–900 m.
Alta., B.C., Man., N.W.T., Nunavut, Ont., Sask., Yukon, Alaska.
Pedicularis parviflora belongs to a complex of taxa [including P. parviflora var. macrodontis (Richardson) S. L. Welsh, and P. pennellii] that have traditionally been treated as species, subspecies, or varieties. Two features unite this group: a highly branched paniculate raceme and a tooth on each medial margin of the galea covered with pyriform glands on the inner surface. Lack of apical teeth sets P. parviflora apart from P. palustris and P. pennellii, which have both sets of teeth.
The distinction of Pedicularis macrodontis is not clear. With a galea that lacks apical teeth, it is clearly associated with P. parviflora, but there are no unique characters to set it apart as a distinct species; all foliar and floral features are very similar. A number of intermediate specimens were seen, suggesting a lack of reproductive barriers; treatment as a variety of P. parviflora, following S. L. Welsh (1974), may be warranted, but further research is required before recognizing it as a taxon.