(capitate lousewort)
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Photo of Pedicularis capitata by Carl Roland
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Capitate lousewort is a small herb with a few hooded yellow flowers borne at the apex of the stem and distinctive fern-like leaves. Plants grow up to 15 cm from a slender
rhizome in shrub and alpine tundra areas across Denali. Unlike other members of the genus,
Pedicularis capitata is often found without any flowering stem, and can be identified by its leaves alone. The leaves are
pinnate, each leaflet pinnately cleft, the
petiole short-hairy—somewhat fern-like. The leaves are green, sometimes with white marks on the edges, and the leaflets are angled horizontally from the vertical leaf. Flowering stalks have 2-5 flowers,
subtended by several
pinnatifid bracts. The
calyx is hairy, divided into elongate lobes that are expanded towards the top, with slightly
crenate margins. The flowers are two-lipped, held upright, the color pale cream to yellow or pink-suffused. The upper petal is curved. The lower lip is three-cleft, longer than it is wide, shorter than the upper lip. The four
stamens are contained within the upper petal, and the
filaments are hairy at the base. Fruits are many-seeded
capsules. The other member of the genus in Denali that is unbranched and yellow-flowered is
Pedicularis oederi, but that plant has stem leaves and many more flowers.
This species blooms mid-season in Atqasook, arctic Alaska (
Williams and Batzli 1982). It is protogenos; the
stigma is receptive 1-2 days before the
anthers of the same flower release their pollen.
Pedicularis capitata is
monoecious with bisexual flowers. The flowers of capitate lousewort are nectar-producing and dependent on bumblebees for pollination. When pollinators are excluded, no seed is produced (
Macior 1975). Like other
Pedicularis species,
P. capitata is a hemi-parasite, stealing some of its nutrients from surrounding plants.
Pedicularis capitata is an amphi-Beringian species with an arctic-alpine distribution. In North America, P. capitata reaches south from Alaska to B.C. and adjacent Alberta, and eastward to Northwest Territory, western Greenland and northern Quebec. In Alaska, P. capitata grows in the alpine and interior uplands, as well as the Arctic slope, its range extending only to northern Southeast Alaska, not in the panhandle. This is a common upland-alpine species in Denali, occurring in suitable habitat across the park, on both sides of the Alaska Range crest.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
This is a subalpine to alpine species. The average occurrence is at 1081 meters, and above 900 m, it occurs in over 50% of the study plots. This species has a slight preference for north-facing slopes, and most commonly occurs on steep slopes (20 and 28 degrees). This is the single most abundant species of the genus in the Park. It is frequently found without flowers.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Well-drained moist to dry sites in the mountains.
