Spiranthes cernua (L.) L.C. Rich.

Nodding Ladies' Tresses

Facts About

Accepted Synonyms: Ibidium cernuum, Ophrys cernua

Spiranthes cernua, commonly called Nodding Ladies' Tresses, is widely distributed throughout central and eastern Canada and the United States, from Texas to Quebec. It produces 2-6 basal leaves which form a rosette and usually wither before the plant flowers; occasionally, 1-2 stem leaves are produced on the lower part of the stem. It bears an inflorescence of up to 12 small, white flowers (rarely yellow or greenish) that form a double, intertwined spiral. The sepals and lateral petals form a cylindrical tube that curves over the column, while the labellum bends downwards; occasionally the center of the labellum is slightly yellow. This species can be distinguished from Spiranthes lacera by its double, instead of single, layered spiral. It can be found in moist fields, woodlands, bogs, marshes, and fens, as well as along roadsides, riverbanks, and in lawns.

Spiranthes cernua is considered globally secure.

Pollination

Although this orchid may be capable of autogamy through agamospermy, Bombus fervidus, Bombus impatiens, Bombus terricola and an unidentified Dialictus bee are known insect pollinators. As in most Spiranthes, bumblebees move upward on the inflorescence in search of nectar. Older flowers at the base of the stalk have more nectar, which makes them an efficient first stop for the foraging bumble bees.

Ecosystem Type

Bogs, disturbed habitats, fens, marshes, meadows, woodlands

Characteristics

Habitat:
terrestrial
Leaf arrangement:
  • alternate
  • basal
Number of leaves on stem:
  • one
  • two
Form of the labellum:
the labellum is not pouch-like
Labellum outline:
the labellum is simple
Main color of labellum:
white
Nectar spur:
absent
Inflorescence type:
the inflorescence is a spike
Labellum characteristics:
the labellum is simple
Labellum length:
6–10.5 mm
Sepal length:
6–12 mm
Plant height:
10–60 cm
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Native to North America

Yes

North American Conservation Status & Distribution

Conservation Status

Select a location to view conservation status:

Conservation and Wetland Status
Global Rank Secure
US Status N/A
Canadian Status Secure

North America Distribution

Adapted from USDA data