''Spiranthes cernua'', commonly called nodding lady's tresses, or nodding ladies' tresses, is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

occurring from

Maritime Canada The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Ca ...

to the eastern and southern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. As the common name suggests ''cernua'' means "nodding", or "bowed" in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

Description

''Spiranthes cernua'' plants grow to tall. They have 1 to 5 narrow, basal, upright leaves, long and wide. The leaves are present during flowering but wilt afterwards. The white flowers are arranged in a spiral around the stem. Each flower is long and consists of 3 sepals and 3 petals, all curved forward to give the flower a long bell shape. Flowers are slightly to strongly nodding (hence the name), with older flowers usually nodding more than new ones. The dorsal sepal (the one at the top) is convex and recurved upwards towards the tip. The lip (bottom petal) curves strongly downwards towards its tip.

Etymology

The genus name, Spiranthes, originated from the Greek words speira (coil) and anthos (flower), describing the spiral flowers common to the orchids in this group. Cernua is from the Greek word cernuus and refers to the drooping or bowing flowers.

Distribution and habitat

The species is native in central and eastern North America, from

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

to the north,

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...

to the west,

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

to the south, and Novia Scotia to the east. ''Spiranthes cernua'' grows in wet meadows, mossy seeps, maritime dune swallows,

Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, peat moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store wa ...

areas around pond and lake edges and along roadsides.

Ecology

The orchid blooms in autumn, from August to November. Native bees, including

bumblebees A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related gener ...

, feed on the nectar and pollinate the plant.

Species complex

Before more recent identification of several separate species ''Spiranthes cernua'' had long been described as a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

, exhibiting different morphologies throughout its range. Charles Sheviak, now retired curator of the

New York State Museum The New York State Museum is a research-backed institution in Albany, New York, United States. It is located on Madison Avenue, attached to the south side of the Empire State Plaza, facing onto the plaza and towards the New York State Capitol. ...

Herbarium, explored this diversity in great detail, eventually describing ''

Spiranthes magnicamporum ''Spiranthes magnicamporum'', commonly called the Great Plains lady's tresses, is a species of orchid that is native to North America. It is primarily native in the Great Plains, but there are outlying populations in the east in areas of former ...

'' to represent large, later-flowering individuals with tuberous roots from the Midwest. More recently, molecular and morphological work has recognized additional

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

in need of description; these newly recognized species are sometimes not closely related to ''S''. ''cernua''. Broadly, the ''Spiranthes cernua'' species complex includes: * '' Spiranthes arcisepala'' (split off as its own species in 2017) * ''

Spiranthes bightensis ''Spiranthes bightensis'', the Atlantic ladies tresses, is a terrestrial orchid native to coasts of the north-eastern United States. Description ''Spiranthes bightensis'' plants look similar to '' Spiranthes cernua'' and ''Spiranthes odorata''. ...

'' (split off as its own species in 2021) * '' Spiranthes casei'' (described in 1975) * ''Spiranthes cernua'' sensu stricto (the original species, described in 1817) * '' Spiranthes incurva'' (re-established as separate species in 2017, ancient hybrid between ''S. cernua'' s.s. and ''S. magnicamporum'') * '' Spiranthes igniorchis'' (first described in 2017) * '' Spiranthes longilabris'' (described in 1840) *''

'' (split off in 1973) *'' Spiranthes niklasii'' (described in 2017, ancient hybrid between ''S. cernua'' and '' S. ovalis'') * '' Spiranthes ochroleuca'' (described in 1932) * '' Spiranthes ovalis'' (described in 1840) * '' Spiranthes parksii'' (described in 1947, in genetic studies revealed to be identical to ''S. cernua'') * '' Spiranthes sheviakii'' (described in 2021) * '' Spiranthes triloba'' (re-described in 2016) * ''Spiranthes'' ×''kapnosperia'' (hybrid between ''S. cernua'' and ''S. ochroleuca'') ''

Spiranthes odorata ''Spiranthes odorata'', marsh lady's tresses or common lady's tresses, is a species of flowering plant in the orchid family, native to the southeastern United States, from Texas eastwards and northwards to Delaware. It grows in moist, partially ...

'' was also formerly included in the ''cernua'' species complex but newer research shows it belonging to a different clade containing most of the remaining Eastern North American Spiranthes species.

Cultivation

A commonly cultivated variety is ''Spiranthes cernua'' 'Chadds Ford', grown because of its larger flowers, ease of cultivation, and other merits. This cultivar is also often labelled as ''

'' however botanically it is neither but a third species called ''

''.

References

{{Taxonbar, from=Q1152261 cernua Orchids of Canada Orchids of the United States Plants described in 1753 Taxa named by Carl Linnaeus