3. Cypripedium reginae Walter (showy lady’s slipper)

Pl. 112 f; Map 462

Flowering stems 30–100 cm long, usually densely hairy, with 1 or 2 (3) flowers. Leaves 3–10 per flowering stem, 15–25 cm long, more than 4 cm wide, narrowly ovate, hairy. Sepals 3.0–4.5 cm long, broadly elliptic, flat or slightly arching, white. Lateral petals 2.5–4.5 cm long, shorter than to about as long as the lip, oblong‑elliptic, flat or slightly arching, not spirally twisted, white. Lip 3–5 cm long, obovoid, the margins rolled inward along the edge of the opening, white, tinged with pink, the inside surface with reddish purple streaks. Column 15–25 mm long, the staminode ovate, white with red spots and yellow areas toward the margins. 2n=20. May–June.

Restricted to the southern portion of the Ozark Division except for disjunct, historical collections from St. Louis and Putnam Counties (northeastern U.S. and adjacent Canada west to North Dakota and Missouri). Seepy ledges of sheltered, north‑facing dolomite bluffs, less commonly along moist stream banks and in fens.

The showy lady’s slipper is arguably one of the most attractive of Missouri wildflowers. Unscrupulous collectors have dug it extensively from the wild for use in gardens. Habitat data from the labels of older herbarium specimens indicate that this species was formerly more common along stream banks, but at present it is found primarily on seepy ledges of north‑facing bluffs, many of these inaccessible to collectors.