Hexalectris revoluta (Curly Crested Coralroot)

Hexalectris revoluta (Curly Crested Coralroot)

Photograph by Rare and Threatened Plants of Big Bend at www.nbii.gov/portal/server.pt (2009)
Family
ORCHIDACEAE
Scientific Name with Author
Hexalectris revoluta Correll
Synonyms
NONE
Common Name
Curly Crested Coralroot
Agency Status
USFWS State of NM USFS BLM Navajo Nation State Rank Global Rank R-E-D Code NMRPTC Status Strategy Status
SEN S1 3-1-2 R SS
Rare Plant Conservation Scorecard Summary
Overall Conservation Status Documented Threats Actions Needed
WEAKLY CONSERVED

No information

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Description
Herbaceous saprophytic perennial; stems 40-50 cm tall, pale pink to rose to tan, leafless except for a few widely spaced bracts; inflorescence a raceme with 10-20 rose-tan to whitish flowers; sepals and petals pale rose-tan with light veining, free and spreading, revolute with outer third rolled back 360 degrees or more; dorsal sepal lanceolate, 2.2 cm long, 0.8 cm wide; lateral sepals elliptic lanceolate, oblique, 2.0 cm long, 0.8 cm wide; petals elliptic to obovate, slightly falcate, 0.6 cm long, 1.8 cm wide; lip broadly elliptic, deeply three-lobed, 1.5 cm long, 1.2 cm wide, white to pale rose-tan, with purple veining on lateral lobes and 5 or 7 raised purple ridges running the entire length of the central lobe; column narrow, curved, 1.5 cm high, white with purple shading at the base; anther cap yellow, minute wings near the apex; pollinia yellow, 8 in 4 pairs; capsules pendant, ellipsoidal, 2.0 cm long, 0.5 cm wide. Flowers May through August.
Similar Species
Species of Corallorhiza may be confused with this genus, but the lips in Corallorhiza have no longitudinal ridges (crests) as in Hexalectris. Hexalectris revoluta is the only Hexalectris in New Mexico with sepals and petals rolled back 360 degrees or more. Hexalectris colemanii also has revolute sepals and petals, but it is confined to southeastern Arizona.
Distribution
New Mexico, Eddy County, Guadalupe Mountains; western Texas; Mexico.
Habitat
Under trees and shrubs at the edges of canyon bottoms; in heavy leaf litter under oaks or in thin humus soils among rock outcrops; 1,950 m (6,400 ft) at Eddy County location, 1,250-2,440 m (4,100-8,000 ft) elsewhere.
Remarks
The absence of a verifying specimen has always cast doubt on the presence of H. revoluta in New Mexico. The inclusion of H. revoluta as a New Mexico rare plant is based on a photograph with precise location information held at the headquarters of Guadalupe Mountains National Park and observed by Tom Todsen, an orchid expert.

Plants from southeastern Arizona formerly called H. revoluta are now named H. colemanii (Kennedy and Watson 2010).

Conservation Considerations
Populations are small and can be easily obliterated by human activity. Documented records are needed to develop the geographic range of this species in New Mexico, but collections must be made judiciously and without digging the rhizome system.
Important Literature

*Coleman, R.A. 2002. The wild orchids of Arizona and New Mexico. Cornell University Press, Ithaca, New York.

*Correll, D.S. 1941. Studies in Isochilus, Mormodes and Hexalectris. Botanical Museum Leaflets 10(1):18-20.

*Flora of North America Editorial Committee. 2002. Flora of North America, volume 26. Oxford University Press, New York.

Kennedy, A.H. and L.E. Watson. 2010. Species delimitations and phylogenetic relationships within the fully myco-heterotrophic Hexalectris (Orchidaceae). Systematic Botany 35(1):64-76.

Information Compiled By
Charlie McDonald 2009; last updated, 2010

For distribution maps and more information, visit Natural Heritage New Mexico