Spiranthes cernua

Spiranthes cernua, commonly called the nodding lady's tresses,[1] is a species of orchid occurring from Maritime Canada to the eastern and southern United States. As the common name suggests cernua means "nodding," or "bowed" in Latin.

Nodding lady's tresses
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Cranichideae
Genus: Spiranthes
Species:
S. cernua
Binomial name
Spiranthes cernua
Synonyms

Description

Spiranthes cernua plants grow up to 100 cm tall. They have 1-5 basal upright leaves, 5-22 cm long and 5-8 mm wide. The leaves are present during flowering but wilt afterwards. The white flowers are arranged in a spiral around the stem. Each flower is 6-12 mm 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), 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.[2][3]

This species blooms in autumn.

Habitat

Spiranthes cernua grows in wet meadows, mossy seeps, maritime dune swallows, Sphagnum areas around pond and lake edges and along roadsides.[3]

Species complex

Before more recent identification of several separate species Spiranthes cernua had long been described as a species complex, exhibiting different morphologies throughout its range. Charles Sheviak, now retired curator of the New York State Museum Herbarium, explored this diversity in great detail,[4] eventually describing Spiranthes magnicamporum to represent large, later-flowering individuals with tuberous roots from the Midwest.[5] More recently, molecular and morphological work has recognized additional cryptic species in need of description; these newly recognized species are sometimes not closely related to S. cernua.[3]

Broadly, the Spiranthes cernua species complex includes:[3]


Cultivation

A commonly cultivated variety is Spiranthes cernua 'Chadds Ford', grown because of its larger flowers, ease of cultivation, and other merits.[6] This cultivar is also often labelled as Spiranthes odorata however botanically it is neither but a third species called Spiranthes bightensis.[7]

References
  1. USDA, NRCS (n.d.). "Spiranthes cernua". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 27 November 2015.
  2. "Spiranthes cernua". North American Orchid Conservation Center (NAOOC), Smithsonian Environmental Research Center. 2018. Retrieved 17 March 2022.
  3. Pace, Matthew C.; Cameron, Kenneth M. (2017). "The Systematics of the Spiranthes cernua Species Complex (Orchidaceae): Untangling the Gordian Knot". Systematic Botany. 42 (4): 640–669. doi:10.1600/036364417x696537. S2CID 90432295.
  4. Sheviak, Charles (1982). "Biosystematic study of the Spiranthes cernua complex". Bulletin of the New York State Museum Science Service. 448 – via Google Scholar.
  5. Sheviak, Charles J. (1973). "A New Spiranthes from the Grasslands of Central North America". Botanical Museum Leaflets, Harvard University. 23 (7): 285–297. doi:10.5962/p.168562. ISSN 0006-8098. JSTOR 41762281. S2CID 91159270.
  6. http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/plant-finder/plant-details/kc/a284/spiranthes-odorata.aspx
  7. PACE, MATTHEW C. (30 April 2021). "Spiranthes bightensis (Orchidaceae), a New and Rare Cryptic Hybrid Species Endemic to the U. S. Mid-Atlantic Coast". Phytotaxa. 498 (3): 159–176. doi:10.11646/phytotaxa.498.3.2. S2CID 235586025. Retrieved 17 March 2022.


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