Spiranthes ovalis

Spiranthes ovalis lesser ladies’-tresses

Plant grows in the wild/spontaneouslyPlant is native to PA

This native orchid species is one of several similar types of lady’s or ladies’ tresses found in this area. It is also known by the common names of lesser ladies’ tresses and oval ladies’ tresses. It can be found throughout the eastern and central parts of North America from Ontario to Texas. This wide range makes it secure, but is often rare or vulnerable in many places. It is considered endangered in Pennsylvania.

The plant grows 2 to 12 inches tall (but usually 7 inches or less) and produces 2 basal and lower stem leaves. These persist through the flowering period. The plant is mostly found in moist forests, but sometimes along marshes and in meadows. Up to 50 small white flowers form on an unbranched stalk (raceme) and are arranged in a tight spiral. Blooming occurs from the bottom towards the top of the stalk. There are six tepals (identical petals and sepals). The corolla has an upper hood consisting of 3 fused tepals, a lower lip consisting of a single tepal, and 2 lateral tepals. As each flower develops, the lateral tepals become free toward the base and extend along the sides of the corolla. Seed capsules eventually release many tiny seeds. The blooming period is from early to late fall.

There are two varieties of this species but the northern variety Spiranthes ovalis erostella is the only one found here. It must be cross-pollinated by insects to produce fertile seeds. The southern variety may self-pollinate. This species is often similar in appearance to the Northern slender ladies’ tresses (S. lacera), but is smaller in size, has no central green spot and is most likely found in forested habitats. It may form hybrids with the marsh ladies’ tresses (S. odorata).

Contributed by: Mark Welchley

Very rare in damp, humus-rich forests.

Found in the southcentral part of the state.

Wetland codes

Flowers in October.

PA status: PE (Enangered)
S-rank:      S1 (Critically imperiled)
G-rank:      G5 (Secure)