north american native orchid journal - at The Culture Sheet

Brown & Folsom: WILD ORCHIDS OF THE WHITE MOUNTAINS OF NEW HAMPSHIRE AND MAINE
Spiranthes cernua (Linnaeus) L.C. Richard
nodding ladies’-tresses
Range: South Dakota east to Nova Scotia, south to Texas and
Florida
In the White Mountains region: locally common
Plant: terrestrial, 10-50 cm tall
Leaves: 3-5; appearing basal or on the lower portion of the
stem; linear-oblanceolate, up to 2 cm wide × 26 cm long;
ascending to spreading; leaves are usually present at anthesis
in most races
Flowers: 10-50; in a spike, tightly to loosely spiraled with 5
or more flowers per cycle, nodding from the base of the
perianth or rarely ascending; bracts with a white or light
green central stripe; sepals and petals similar, lanceolate;
perianth white, ivory; lip oblong, broad at the apex, the
central portion of the lip, in some races, creamy-yellow or
green; the sepals approximate and extending forward
sometimes arching above the flower; individual flower size
0.6-10.5 mm
Habitat: wet to dryish open sites, lightly wooded areas, moist
grassy roadsides, etc.
Flowering period: late August to October
Of all of our native orchids in North America, Spiranthes
cernua is the most difficult for which to give a simple, concise
description and narrative. Because it is a compilospecies–one
that has gene flow from several different similar species–
plants in different geographic areas have strong resemblances
to the basic diploid species contributing that unidirectional
gene flow. In northeastern North America we are somewhat
fortunate that the only basic diploid Spiranthes that contributes gene flow at this time is S.
ochroleuca. The so called ―Quebec race‖ shows possible gene flow from S. casei, but that
remains to be proven. That is not to say that identification of S. cernua plants is always easy—
quite to the contrary. Because the plants are apomictic—not fertilized in the traditional sexual
manner, but producing seed (actually minute plantlets) directly without fertilization–local
races occur that are quite distinctive.
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