October Ladies-tresses

Description:

Two variations of Spriranthes ovalis exist in North America: variation ovalis and variation erostellata. The following is a description of Spiranthes ovalis cited from Radford et. al., 1968 and Flora of North America, 2003. A descripton of both variations are given below S. ovalis under separate headings.

Spiranthes ovalis is a small herbaceous orchid that is glabrous below and somewhat pubescent above (Radford et. al., 1968) originating from a few slender, spreading to descending, roots mostly to 0.5 cm diameter. The species grows to approximately 5 to 40 cm in height (Flora of North America, 2003). Its basal leaves number 2 to 4 and are broad, oblong-elliptic to oblanceolate or linear-lanceolate. The leaves are 5 to 15 cm in length by 6 to 15 mm in width and obtuse to acute in shape. From August through November, terminal flower spikes develop and are somewhat congested and slender composed of several ranks of small, pure white flowers (Radford et. al., 1968). The spikes are tightly spiraled, usually 3 flowers per cycle of spiral, but rarely loosely spiraled in depauperate plants. The rachis is pubescent with some trichomes that are clavate to capitate. The glands are obviously stalked (Flora of North America, 2003). The flowers are elongate-ovoid to cylindrical and pyramidel at the apex and 2 to 10 cm in length (Radford et. al., 1968). The sepals are distinct to the base, slightly spreading, 3.5 to 6.1 mm in length by 1 to 1.5 mm in width. The petals are lanceolate, 6 mm in length by 1 mm in width. The lip is ovate, 5 mm in length by 3 mm in width and the apex has a finely crisped margin (Flora of North America, 2003). The callosites are slender, rarely stout, strongly incurved. The column is approximately 2 mm in length (Radford et. al., 1968). The ovary is approximately 3 to 8 mm. S. ovalis produces monoembryonic seeds (Flora of North America, 2003).

October ladies-tresses (Spiranthes ovalis var. erostellata):

In Spiranthes ovalis var. erostellata, the flowers are never quite fully open, and the ovaries are simultaneously swollen on each flower (Flora of North America, 2003). The petals are approximately 6 mm in length (Weakley, 2002) and the sepals are 3.5 to 5 mm in length. The rostellum and viscidium are absent (Flora of North America, 2003). Spiranthes ovalis var. erostellata is self-pollinating and may be more adapted to disturbance than var. ovalis (NatureServe, 2003).

October ladies'-tresses (Spiranthes ovalis var. ovalis):

Spiranthes ovalis var. ovalis is allogamous and the rostellum and viscidium are present. The flower sepals are approximately 4 to 6.1 mm. The rostellum is well developed and the viscidium is linear-lanceolate (NatureServe, 2003). Spiranthes ovalis var. ovalis (which was differentiated in 1983) only occurs in the southern United States and is less widespread than variation erostellata. Variation ovalis is cross-pollinating compared to variation erostellata which is self-pollinating. The variation ovalis is scattered over its range and generally considered uncommon to rare (NatureServe, 2003) and occuring from 0 to 300 meters in elevation (Flora of North America, 2003).

Habitat:

Both variations uncommonly (Weakley, 2002) inhabits moist shady woods, thickets, and margins of wetlands (Radford et. al., 1968), and Weakley (2002) reports the species is uncommon in swamp forests and bottomland forests. Flora of North America (2003) reports the species inhabits moist, rich woodlands, thickets, old fields, second growth woodlands, wooded hillsides from ranging from 0 to 900 m elevation depending on variation.