1. Parnassia grandifolia DC.
Pl. 477 e, f;
Map 2180
Plants perennial
herbs, usually with short rhizomes, glabrous, but often with areas of minute
rusty brown dots. Aerial stems 12–45 cm long, erect, unbranched. Leaves in a
basal rosette, long-petiolate, the petiole broadened toward the tip, also a
solitary bractlike leaf positioned at or below the midpoint of the flowering
stem, this sessile or nearly so. Stipules absent. Leaf blades simple,
relatively thick and leathery, those of the basal leaves 2.5–10 cm long, those
of the stem leaves 0.6–4.0 cm long, both types oblong-ovate or broadly ovate to
nearly circular, rounded to broadly and bluntly pointed at the tip, broadly
rounded to truncate or shallowly cordate at the base, mostly with 7 or 9
palmate main veins, the margins entire. Inflorescences of solitary flowers
naked at the aerial stem tips. Flowers perfect, actinomorphic, hypogynous or
slightly perigynous. Hypanthium absent or nearly so. Sepals 5, fused at the
very base, 3–4 mm long, elliptic-ovate, usually prominently veined, with broad,
thin, white to transparent margins, ascending at flowering, persistent and
becoming reflexed at fruiting. Petals 5, 12–22 mm long, spreading,
oblong-elliptic to elliptic-ovate, white, with 7–11, prominent, green, mostly
parallel veins (the outermost pair with several branches toward the margin).
Stamens 5, alternating with the petals, the relatively large anthers attached
toward the cordate base, pink. Staminodes 5, opposite the petals, somewhat
longer than the fertile stamens, each divided at or toward the base into 3
filament-like stalks, each stalk with a glistening capitate tip. Pistil 1 per
flower, of 4 fused carpels. Ovary superior, bright green, with 1 locule, with
numerous ovules, the placentation parietal. Style absent or nearly so, the 4
stigmas club-shaped to more or less capitate, outwardly curved. Fruits
capsules, 11–16 mm long, ovoid, dehiscing longitudinally, with numerous seeds.
Seeds 0.7–1.4 mm long, irregularly ovate to tetrahedral in outline, somewhat
flattened, the outer covering loose, somewhat wrinkled, and winglike, the
surface, with a minute network of hexagonal pits, brown. 2n=32. August–October.
Scattered in the
south-central and eastern portions of the Ozark Division (southeastern U.S.
west to Missouri and Texas). Fens and moist calcareous seeps along streams and
bluffs.
Steyermark
(1963) wrote that, “This species brightens the swampy meadows in autumn with
the open white flowers...” The white petals with their prominent green veins
make this a most attractive wildflower. The rosettes of thick leaves also are
distinctive, even when the plants are not flowering. Regrettably, P. grandifolia
is considered of conservation concern in nearly every state within its
distributional range. In Missouri, where its status appears to be reasonably
secure, it is considered an indicator of high-quality calcareous seepage
communities, especially fens.