Spiranthes lacera (Raf.) Raf.

Slender Ladies' Tresses


CC = 6
CW = 0
MOC = 55

© SRTurner

Family - Orchidaceae

Habit - Perennial forb.

Stems - Flowering stems 10-35 cm long, with usually sparse, glandular hairs.

Leaves - Basal leaves 2-4, usually absent at flowering time, 1-4 cm long, ovate to elliptic, glabrous.

Inflorescence - Terminal helical spike. Flowers appearing as a single spiral along the flowering stems or rarely no spirals discernable.

Spiranthes_lacera_inflorescence.jpg Inflorescence.

© SRTurner

Flowers - 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. Stamens 1.

Spiranthes_lacera_flowers.jpg Flowers.

© SRTurner

Spiranthes_lacera_flower.jpg Flowers.

© DETenaglia

Spiranthes_lacera_flower2.jpg Flowers.

© DETenaglia

Fruits - Ascending capsules, elliptical in outline with longitudinal ridges.

Flowering - August - October.

Habitat - Dry upland forests, upper slopes of bluffs, dry upland prairies, old fields, powerline cuts, cemeteries, lawns, other disturbed, open situations, particularly in acidic, dry, cherty or sandy soils.

Origin - Native to the U.S.

Lookalikes - Other species of Spiranthes.

Other info. - This small species can be found throughout most of Missouri, though is rare or absent in the northwestern and southeastern corners of the state. It occurs througout the eastern half of the U.S. and also ranges into Canada. The spiral arrangement of small, white flowers instantly identifies the plant as a Spiranthes, though precise species identification can sometimes be a bit tricky. Characters which point to S. lacera include a single-ranked spiral of relatively small flowers, with these having a green coloration in the throat, and glandular hairs on the inflorescence axis. A similar species, S. tuberosa Raf., has even smaller flowers which are all white. Spiranthes lacera is less conservative than most other orchids and often occurs in relatively disturbed areas.

Photographs taken in Brown Summit, NC., 8-6-02 (DETenaglia); also at Cuivre River State Park, Lincoln County, MO, 8-16-2010, ad at Port Hudson Lake Conservation Area, Franklin County, MO, 8-28-2014 (SRTurner).