Wednesday, January 10, 2018

[Botany • 2018] The Taxonomic Identity of Three Varieties of Lecanorchis nigricans (Vanilleae, Vanilloideae, Orchidaceae) in Japan

 Lecanorchis nigricans var. nigricans 
Lecanorchis nigricans var. patipetala
 Lecanorchis nigricans var. yakusimensis
emend. Suetsugu & Fukunaga

in Suetsugu, Shimaoka, Fukunaga & Sawa, 2018.

To elucidate the taxonomy of the Lecanorchis nigricans Honda, 1931 species complex, the present study investigated the detailed morphology of three L. nigricans varieties in Japan. While L. nigricans var. patipetala Y.Sawa, 1980 and L. nigricans var. yakusimensis T.Hashim., 1990 have often been treated as synonyms of L. nigricans var. nigricans, the present study demonstrates that the three varieties are morphologically distinct. More specifically, L. nigricans var. nigricans only produces complete cleistogamous flowers and is distinct from the plants currently called “Lnigricans”, which are identical to the chasmogamous variety L. nigricans var. patipetala. The other chasmogamous variety L. nigricans var. yakusimensis can be easily distinguished from L. nigricans var. patipetala by its more spatulate tepals and higher cucullate lip. Therefore, the present study provides emended description of the three Lnigricans varieties based on type specimens and specimens collected from type localities. In addition, the isotype specimen of L. nigricans var. patipetala is designated as the lectotype because the holotype has been lost.

Keywords: Japan, Lecanorchis nigricans var. yakusimensisLecanorchis nigricans var. patipetalaLecanorchis taiwaniana, lectotypification, mycoheterotrophy, taxonomy

A Flowering plant and B cleistogamous flowers of Lecanorchis nigricans var. nigricans in Oka, Kamitonda, Wakayama, Japan (its type locality). Photographed by Hirokazu Fukunaga 

C Flowering plant and D a flower of Lecanorchis nigricans var. patipetala in Haruno, Kochi, Japan.   E Flowering plant and F a flower of Lecanorchis nigricans var. yakusimensis collected in Hanaage River, Yakushima, Japan (its type locality).
Photographed by Hiroaki Yamashita.

Figure 1. Photographs of three varieties of Lecanorchis nigricans in their natural habitats.
A Flowering plant and B cleistogamous flowers of Lecanorchis nigricans var. nigricans in Oka, Kamitonda, Wakayama, Japan (its type locality). Photographed by Hirokazu Fukunaga
C Flowering plant and D a flower of Lecanorchis nigricans var. patipetala in Haruno, Kochi, Japan. Photographed by Hisanori Takeuchi
  E Flowering plant and F a flower of Lecanorchis nigricans var. yakusimensis collected in Hanaage River, Yakushima, Japan (its type locality). Photographed by Hiroaki Yamashita.

Taxonomic treatment 

Lecanorchis nigricans Honda emend. Suetsugu & Fukunaga

Type: JAPAN, Wakayama Pref., Nishimuro County, Iwata, Oka, date unknown 1931, K. Kashiyama s.n. (holotype TI!; Isotype TI!).

• Lecanorchis nigricans var. nigricans

• Lecanorchis nigricans Honda var. patipetala Y.Sawa emend. Suetsugu & Fukunaga

• Lecanorchis nigricans Honda var. yakusimensis T.Hashim. emend. Suetsugu & Fukunaga

Kenji Suetsugu, Chie Shimaoka, Hirokazu Fukunaga and Shinichiro Sawa. 2018. The Taxonomic Identity of Three Varieties of Lecanorchis nigricans (Vanilleae, Vanilloideae, Orchidaceae) in Japan. PhytoKeys. 92: 17-35.  DOI: 10.3897/phytokeys.92.21657

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