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.

Spiranthes lacera is perhaps the most easily identified species of Spiranthes found in Wisconsin. The green spot on the labellum is distinctive.

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.

July 5-September 15.

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.

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