Long-horned habenaria, Michaux’s orchid

Orchis quinqueseta Michaux, Fl. Bor.-Amer. 2: 155. 1803; Habenaria habenaria (Linnaeus) Small; H. macroceratitis Willdenow; H. quinqueseta var. macroceratitis (Willdenow) Luer

Plants terrestrial, erect, 2–9 dm. Leaves scattered along stem and gradually reduced distally, or occasionally grouped toward base and abruptly reduced to bracts; blade wide-spreading to ascending, elliptic-oblong to oblanceolate, 5–25 × 2–6 cm. Inflorescences: floral bracts ascending to appressed, foliaceous, ovate to lance-acuminate, 15–28 × 7–15 mm. Flowers ascending, showy; sepals green; dorsal sepal shallowly concave, 6–13 × 5–10 mm; lateral sepals descending-spreading, 8–16 × 4–7 mm; petals white, lamina ascending, falcate, 6–15 × 2 mm, lateral lobe spreading-recurved, filiform, nearly equal to more than 2 times length of petal; lip white, middle lobe descending, linear, 8–20 × 2–3 mm, lateral lobes spreading, descending, filiform, nearly equal to more than 2 times middle lobe, apices recurved; spur slender, often markedly clavate, 4–18 cm; ovaries 2–3 cm. Capsules on short pedicel, nearly erect, 15–30 × 5–10 mm.

Flowering Aug. Dry to wet pine savannas and mixed flatwoods, hammocks, swamps, meadows, and roadsides; 0--100 m; Ala., Fla., Ga., La., Miss., S.C., Tex.; Mexico; West Indies; Central America; South America.

Spur length is extraordinarily variable in Habenaria quinqueseta as here delimited. Recognition of H. quinqueseta var. macroceratitis, a long-spurred variety with a more tropical distribution, has been proposed (C. A. Luer 1972), restricting var. quinqueseta to the United States. Spur length varies continuously, and recognition of segregates based on this feature alone is not warranted (D. S. Correll 1950). Recent study, however, has shown Habenaria macroceratitis Wildenow to be distinct (P. M. Brown 2000c). Both H. quinqueseta and H. macroceratitis vary in spur lengths, and this situation has obscured other differences. This information did not appear in time to be accommodated fully in the present treatment.

The two species may be distinguished as follows (P. M. Brown 2000c):

SELECTED REFERENCE

Brown, P. M. 2000c. Recent taxonomic and distributional notes from Florida 7. The genus Habenaria. N. Amer. Native Orchid J. 6: 148–158.