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Published In: Herbarium Rafinesquianum 44. 1833. (Herb. Raf.) Name publication detail

Project Name Data (Last Modified On 7/9/2009)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native


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2. Spiranthes lacera (Raf.) Raf. (slender ladies’ tresses)

Pl. 117 h–j; Map 482

S. lacera var. gracilis (Bigelow) Luer

S. gracilis (Bigelow) L.C. Beck

Flowering stems 10–35(–55) cm long, with usually sparse, glandular hairs. Basal leaves 2–4, usually (but not always) absent at flowering time, 1–4 cm long, ovate to elliptic, glabrous. Flowers appearing as a single spiral along the flowering stems or rarely no spirals discernable. Sepals and lateral petals 3.5–6.5 mm long, white, the lateral sepals free to the base or nearly so, only slightly spreading, oriented parallel to the rest of the perianth or nearly so. Lip 4.5–5.5 mm long, oblong, the margins irregularly toothed toward the tip, white with a green area in the middle of the inner surface. Column 2 mm long, green. 2n=30. August–October.

Scattered nearly throughout the state except the far northwestern corner (eastern U.S. west to Texas and Nebraska, Canada). Dry upland forests, upper slopes of bluffs, dry, upland prairies, mostly on acidic substrates; also in old fields, powerline cuts, cemeteries, lawns, and other disturbed, open situations, particularly in dry, cherty or sandy soils.

Spiranthes lacera is perhaps the least conservative (in terms of fidelity to a single community) species of orchid in the state, occurring in a variety of disturbed and undisturbed habitats. It differs from the similar S. tuberosa in the green spot on the lip of each flower, the somewhat longer, sparsely glandular‑hairy spikes, and the 2 or 3 (rather than usually 1) tubers per plant.

In typical S. lacera, the flowers are arranged loosely in a long, gentle spiral (Pl. 117i), but in scattered populations in the Ozarks occur plants with the flowers more tightly spaced in condensed spirals (Pl. 117j), and rarely not recognizable as spirals. Such plants have been segregated as var. gracilis (Bigelow) Luer. However, the tighter‑flowered plants are not sharply distinguished from those with the looser inflorescence structure, and the recognition of varieties seems arbitrary for many of the herbarium specimens. Thus, the separation of S. lacera into varieties seems unwarranted.



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