Wednesday, December 21, 2022

[Botany • 2022] Aphyllorchis periactinantha (Orchidaceae: Epidendroideae: Neottieae) • A New Mycoheterotrophic Species from peninsular Thailand


Aphyllorchis periactinantha A.Chantanaorr. & Chantanaorr., 

in Chantanaorrapint & Chantanaorrapint, 2022. 
photographed by S. Chantanaorrapint

Abstract
A new orchid species from southern Thailand, Aphyllorchis periactinantha, is described and illustrated. The novelty is characterized by the subactinomophic flowers, the concave labellum, not divided into hypochile and epichile, the reduced staminodes, the shallowly bilobed stigma and the semicircular rostellum. A key to the species of Aphyllorchis in Thailand is updated.

Keywords: achlorophyllous orchid, dipterocarp forest, Epidendroideae, peloric flower, Thai-Malay Peninsula, Ton Nga Chang Wildlife Sanctuary

Aphyllorchis periactinantha A.Chantanaorr. & Chantanaorr.
A flower, lateral view B flower, top view C floral bract D column and labellum, side view E dorsal sepal F, G lateral sepals H, I petals J labellum K column and anther cap in ventral view L, M anther caps.
Drawn by S. Chantanaorrapint.

Aphyllorchis periactinantha A.Chantanaorr. & Chantanaorr. in situ
 A habit B inflorescence C flower in front view D flower in oblique view with stingless bee (Tetragonula sp.) E column in ventral view F immature fruits G rhizome and roots
A–E, G photographed by S. Chantanaorrapint F by C. Leeratiwong.
 
 Aphyllorchis periactinantha A.Chantanaorr. & Chantanaorr., sp. nov.
 
Diagnosis: Similar to A. anomala, but differs in having a concave labellum without purple veins, acute at the apex, and a semicircular rostellum.

Etymology: Greek prefix peri-, about, actis, ray or radiate, and anthos, flower, alluding to subactinomorphic flowers.


 Amonrat Chantanaorrapint and Sahut Chantanaorrapint. 2022. Aphyllorchis periactinantha (Orchidaceae, Neottieae), A New Mycoheterotrophic Species from peninsular Thailand. PhytoKeys. 215: 107-115. DOI: 10.3897/phytokeys.215.91458