Spiranthes odorata (Nutt.) Lindl. - Fragrant Ladies' Tresses


 

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Spiranthes odorata - (image 1 of 5)

 

Taxonomy

Family: Orchidaceae

Habitat

Seasonally inundated sites including swamps and forested floodplains; may bloom while emerging from shallow water.

Associates

 

 Distribution

Delaware and Tennessee south to Florida and Texas. Disjunct in New York and Kentucky.

Morphology

Perennial to 100 cm. Roots several, horizontally spreading, slender, mostly to 0.3 cm diam. Leaves persisting through anthesis, basal, gradually or occasionally abruptly reduced upward on stem, base of blade sheathing stem or narrowed to broad petiole over 7 mm wide, ascending to spreading (rigidly so because of aerenchymatous thickening of blade); blades on proximal cauline sheaths spreading-recurved, frequently also on distal (then extending to inflorescence), elliptic to oblong- or linear-oblanceolate, to 52 4 cm. Spikes tightly spiraled, 34 flowers per cycle of spiral; rachis moderately pubescent, some trichomes capitate, glands obviously stalked. Flowers nodding, white, urceolate to gaping, claw of lip at low (less than 30) angle to lamina, base appearing only slightly inflated; sepals distinct to base, 418 mm; lateral sepals loosely associated with dorsal and petals or spreading, sometimes arching above flower; petals lanceolate to elliptic-lanceolate, 418 mm, apex acute to obtuse or emarginate; lip often yellow or green centrally, rhombic-ovate to ovate or lance-ovate, 416 (4)79.5 mm, fleshy, margins lacerate-crenulate, glabrous; veins several, branches parallel; basal calli incurved, prominent, sometimes conic in small flowers, 0.22.5 mm; viscidia linear to linear-lanceolate; ovary 48 mm. Seeds monoembryonic. 2n=30. 

Notes

Flowers late September to December.

Wetland indicator: NA

This species has long been confused with S. cernua, from which it differs in having wider leaves (1.5+ cm), stoloniferous roots, and monoembryonic seeds. The lip is also thicker, yellower, and less crisped along the margins. Spiranthes bightensis is an apparent allopolyploid derived from hybridization of these two species.

 References

McMullen, J.M., M. Hough, M.A. Young, and C.L. Landis. 2021. Discovery of Spiranthes odorata (Nutt.) Lindl. (fragrant ladies-tresses) in central New York. Native Orchid Conference Journal 18(2): 38-50.

Pace, M.C. 2021. Spiranthes bightensis (Orchidaceae), a new and rare cryptic hybrid species endemic to the U.S. Mid-Atlantic coast. Phytotaxa 498(3): 159-176.

Pace, M.C. and Cameron, K.M. 2017. The systematics of the Spiranthes cernua species complex (Orchidaceae): Untangling the Gordian Knot. Systematic Botany, 42(4):1-30.

Sheviak, C.J. 1982. Biosystematic study of the Spiranthes cernua complex. New York State Museum Bulletin No. 448.

Sheviak, C.J. and P.M. Brown. 2002. Spiranthes. pp. 498, 499, 530, 537. In: Flora of North America Editorial Committee, eds., Flora of North America north of Mexico, vol. 26. Oxford University Press, New York, NY. Available at http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=131021 [accessed March 2021].


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 Michael Hough 2021