Spiranthes, commonly called Ladies'-tresses, is a genus in the Orchidaceae family. It has a wide distribution throughout the world and is found in both the northern and southern hemispheres. Species are perennial, terrestrial orchids with clustered, tuberous or rarely fibrous, fleshy roots. The leaves are basal or occasionally cauline, variable, from broadly ovate to elliptic, or absent at flowering. Flowers are shades of white or occasionally pink, tubular, and arranged more or less spirally twisted.
Spiranthes australis (R.Br.) Lindl, syn. Spiranthes sinensis subsp. australis (R.Br.) Kitam. is the only species the occurs in Australia. Some sources are still including it as a subspecies of another species found in Europe and Asia, but most authorities in Australia consider it a separate species. Commonly known as Austral Ladies' Tresses or the Pink Spiral Orchid, it is widespread and common and found in many states in Australia occurring in moist to wet soils in swamps, marshes, near streams and in sub-alpine grasslands at elevations of 20 to 450 meters. It flowers from spring through summer and grows from 20 to 45 cm (10 to 18") high. Growing from long tubers, plants have three to five grassy leaves and scented light pink to deep pink flowers with a white labellum with curled, fringed or toothed margins. The flowers wind in a spiral ribbon around the stem to form a sinuous, corkscrew spike up the slender green stem. Photos 1 and 2 from Andrew Harvie. The last image by Martin Bohnet may be this species or another in the S. sinensis complex, but demonstrates the tininess of these flowers compared to a ten Eurocent coin.
Spiranthes odorata (Nutt.) Lindl. (syn. Spiranthes cernua var. odorata (Nutt.) Correll) is a fragrant species smelling of vanilla or jasmine commonly known as nodding ladies tresses that is found in coastal regions of the southeastern United States from Virginia to Florida and west to Texas. It flowers from fall through winter. It has yellowish white flowers.
'Chadds Ford' is the form most likely to be in cultivation. Dick Ryan rescued this plant from a wet ditch near Bear, Delaware in the 1960s when its habitat was about to be destroyed. Although it is a bog plant, growing instructions found on the internet report it can be grown in full sun and moist to wet, acidic soils to dry shade in a mix of sand, leaf compost, and peat or orchid medium. Photographs from Mary Sue Ittner of a plant shared at a gathering of the Pacific Bulb Society that she was told could be grown and kept uniformly moist by being placed in a saucer of water. It has a long blooming time in fall. It can apparently be reproduced from tuber divisions and grown from seed.
Spiranthes romanzoffiana is found in various habitats: moist to wet meadows, tundra, marshes, fens, prairies, stream banks, seeps, coastal bluffs, dunes growing from 0-3400 m in North America and Europe. It flowers June-October. Known as hooded ladies tresses, the 10-40 cm tall flower spike is a downy dense spiral much like a woman's braided hair. Spikes usually are very tightly spiraled with three flowers per cycle of spiral, but they can be rarely loosely spiraled or with more than 5 flowers per cycle. The hooded flowers are white to ivory, occasionally yellowish white with a lip petal constricted near the base and marked with greenish veins. There is some variation in forms, especially when it grows near Spiranthes porrifolia. Photos taken by Mary Sue Ittner and Bob Rutemoeller on the Mendocino Sonoma Coast at Manchester State Beach and Salt Point State Park.
Spiranthes spiralis is distributed from Europe, North Africa, Caucasus and North Iran eastwards to the Western Himalayas. It is found in dry grassy places, meadows, garigue, heaths, and pine woodland. Growing from 5 to 30 cm, it is tuberous with a hairy stem, shiny oval-elliptical foliage in a basal rosette, and white flowers borne in a slender spiral 3 to 12 cm long. The outer 2 sepals are spreading; the upper sepal and the petals fuse to form a tube with a yellowish-green lip with notched edges that look frayed. The flowering stem begins to grow in summer before the leaves. Leaves develop in late summer to fall and survive until summer when the wither. Photos taken by Bob Rutemoeller and Mary Sue Ittner along the Amalfi Coast in Italy October 2012.