(hooded ladies'-tresses)
Select an option below for more information on this species
Photo of Spiranthes romanzoffiana by Adolph Murie
|
Hooded ladies tresses is a wetland orchid with a spiraling
spike of delicate white flowers. This species grows in wet meadows in the boreal zone in Denali on both sides of the Alaska Range. Plants grow 10-30 cm tall, with a few
linear basal leaves. The roots are fleshy and tuberous. Stem leaves are sheathing and alternate. The upper leaves are highly reduced
bracts. The
inflorescence is a dense cylindrical
spike, with flowers arranged in spirals of four. Flowers are
bilaterally symmetric and have specialized morphology typical to orchids. Flowers are white at the tips, becoming greenish at the base. The upper petal and the two
sepals are fused to form a curved hood, the lower lip curves back towards to stem. Fruits are cylindric
capsules containing many tiny seeds.
Spiranthes romanzoffiana could potentially be confused with
Platanthera dilatata, another orchid with a
spike of spiraling white flowers, if one hadn't seen both species. In that species, the flowers have elongate, wing-like petals.
Spiranthes romanzoffiana has a much thicker, tightly spiraled
inflorescence, and the flowers are more tubular.
Hooded ladies tresses is perennial. The flowers appear in mid-summer and are protandrous-the
stamens developing before the
stigmas.
Like all orchids, each flower contains a set of pollinia. These packages of pollen attach to bees, which in turn pollinate other flowers. Hooded ladies tresses is an outcrossing species (
Catling 1982). The
capsules release hundreds of minute, dust-like seeds, which are wind-dispersed. Like all orchids, the species is dependent on its
mycorrhizae for its establishment and nutrition.
Spiranthes romanzoffiana occurs broadly in North America and is endangered in the British Isles (Ireland & western Scotland). In North America, the species occurs throughout Canada, except for the high arctic, to the Great Lakes and New England in the East, and in most of the Western states, with an interrupted distribution in the Southwest. In Alaska, Hooded lady's-tresses is known from the southern edge of the Brooks Range, to Unimak Island in the eastern Aleutians, through the mainland of Alaska and southeastern panhandle. In Denali, this species occurs in boreal lowlands of the Park, both north and south of the Alaska Range.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
Hooded lady's tresses grows from low elevations to the subalpine, average site at 370 m. This species is almost always on flat areas, the few plants found above five degrees incline in Denali were on low south-facing slopes.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
S. romanzoffiana is a wetland species, found in fens, sedge meadows and Sphagnum bogs.
Wet sites.
1 thought on “Eco-atlas Page”
Comments are closed.