(yellow thimbleweed)
Select an option below for more information on this species
Photo of Anemone richardsonii by Jacob Frank
|
Anemone richardsonii is a creeping herb with solitary yellow flowers found in streambanks, moist thickets and lush meadows that occurs from the lowlands into the alpine zone. Plants grow up to 5-20 cm tall from a slender
rhizome. Plants will send up single, long-
petioled leaves from the
rhizome, and flowering stems with a pair of opposite leaves beneath the bud. Basal leaves are
palmately lobed, round in outline, with the margins
toothed. Stem leaves are 3-cleft,
toothed, and without
petioles. Flowers have approximately six yellow
tepals (looking like petals), which are hairy on the underside. The 25-55 yellow
stamens surround a conic
compound ovary, with many
styles. After flowering, the plant matures to have a rounded head of many dry fruits (
achenes). The
achenes are hairless, with a long curved beak, which is also hooked at the apex. This is the only yellow-flowered anemone species in the Alaskan flora, and is also the only anemone with hooked, hairless
achenes.
Yellow thimbleweed flowers early. This species is perennial.
Anemone richardsonii is
monoecious, with bisexual flowers. Many species of
Anemone are both self-fertile and out-crossed (
Lindell 1998), others are strictly out-crossing (
Douglas and Cruden 1994). Though
A. richardsonii's pollination has not been studied, other species of the genus with similar flowers are bee-pollinated. The breeding system of yellow thimbleweed is unknown. After flowering, the plant matures to have a rounded head of many dry fruits (
achenes). The
achenes have a hooked beak, which aids in dispersal.
Yellow thimbleweed is an amphi-Beringian species that occurs across Canada and Alaska, reaching into Siberia to the west. In Denali, Anemone richardsonii occurs across the Park in suitable habitat, and is most common in the hills, mountains and major river floodplains.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
Yellow thimbleweed has the widest range of elevations of the Anemones: 91 to 1753 m, peak frequency at 900-1100 meters. It is common everywhere but the steepest slopes (>28 degrees). It shows a slight preference for north-facing slopes.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Moist sites, often in riparian areas.