Spiranthes lacera (Raf.) Raf.
Slender ladies'-tresses
The specific epithet lacera is the Latin meaning "torn,"
referring to the erose or fringed margin of the labellum of this species.
DESCRIPTION:
Plant sparsely pubescent above the leaves, 10-40 cm tall (including
inflorescence), arising from a cluster of fleshy, thick roots, appearing
tuberous. Leaves 2-4, basal, ovate to elliptical, 2-5 cm long and
1-2 cm wide, fugacious (withering at flowering) in var. gracilis,
persisting in var. lacera. Inflorescence a sparsely downy,
spicate raceme of 20-40 tiny white flowers, typically tightly spiralled,
10-40 cm tall, each flower subtended by an elongate, ovate-lanceolate bract.
Sepals lanceolate-acuminate, 3-5 mm long and about 2 mm wide, the
lateral sepals with margins inrolled and tips recurved-spreading, dorsal
sepal connivent with petals to form a hood over the column and labellum,
sepals snowy white. Petals linear-lanceolate, 3-5 mm long and 1-2
mm wide, colored as the sepals and closely appressed to the sepals, tips
of sepals and petals reflexed slightly. Labellum oblong, 3-5 mm long
and 1.5-3 mm wide, white and crystalline in texture, with a dark green center
that does not extend to the apex, the margins inrolled, the apex slightly
bent downwards, margin erose, the base of the labellum with two small calli.
SIMILAR SPECIES: Spiranthes lacera is perhaps the most easily
identified species of Spiranthes found in Wisconsin. The green spot
on the labellum is distinctive.
HABITAT: Spiranthes lacera is found in moist to dry, typically
sandy, acidic soil. Habitats in Wisconsin include jack-pine barrens and
open pine woods to thin-soil prairies.
FLOWERING DATES: July 5-September 15.
POLLINATION: Catling (1983b)
collected bumblebees pollinating Spiranthes lacera.
DISCUSSION: Many taxonomists recognize two varieties of Spiranthes
lacera: S. lacera var. gracilis, with the leaves fugacious
and the lowermost flowers closely spaced; and S. lacera var. lacera,
with the leaves persistent and the lowermost flowers +/- widely spaced.
In the second edition (1987) of "Orchids
of the western Great Lakes Region," Fred Case implied that he felt
that the two varieties tend to intergrade in our area. My experience coincides
with his, and so I only recognize S. lacera here, and do not make
any varietal distinctions.
WI DISTRIBUTION: 
U.S. DISTRIBUTION:
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