Friday, June 26, 2015

[Botany • 2015] Thismia nigricans Chantanaorr. & Sridith • A New Species of Thismiaceae from Phang-Nga, Southern Thailand

Thismia nigricans  Chantanaorr. & Sridith
A–B. Habit, C–D. Flowers, E. Longitudinal section of flower, F. Fruit. 
All photos by S. Chantanaorrapint


Thismia nigricans Chantanaorr. & Sridith is described and illustrated as a new species from Sri Phangnga National Park, southern Thailand. A taxonomic description, illustrations of the new species and a comparison with the related species T. angustimitra Chantanaorr. and T. mirabilis K. Larsen are presented.

Keywords: achlorophyllous, mycoheterotrophic, Thailand, Thismia nigricans, Monocots

Taxonomic Treatment

Thismia nigricans Chantanaorr. & Sridith, sp. nov. (Figs. 1 & 2A–F)
Thismia nigricans is similar to Tangustimitra Chantanaorr., but differs in having glabrous filaments, the apex of annulus divided into 3 lobes without golden-brown hairs, and the mitre bearing more irregularly dentate ribs.

Figure 2. A–F. Thismia nigricans Chantanaorr. & Sridith: A–B. Habit, C–D. Flowers, E. Longitudinal section of flower, F. Fruit.
G–J. T. angustimitra Chantanaorr.: G. Habit, H–I. Longitudinal section of flowers, J. Top view of mitre.
K–M. T. mirabilis K. Larsen: K. Habit, L. Longitudinal section of flower, M. Top view of mitre.
All photos by S. Chantanaorrapint.  

Type:— Thailand. Phangnga: Kura Buri, Bang Wan, Sri Phangnga National Park, 08°59’34.06’’ N, 098°27’5.22’’ E, 56 m, 3 August 2014, S. Chantanaorrapint & C. Promma 3897 (holotype, PSU!, isotype, BKF!) 

Distribution:— Known only from the type locality in Sri Phangnga National Park, Phangnga Province, Thailand.

Habitat and Ecology:— The type specimens were found growing with other mycotrophic plants such as Epirixanthes sp. and Thismia javanica Smith (1907: 32), amongst leaf litter, under shade in evergreen forest, ca. 50 m above sea level.

Phenology:— Flowering and fruiting during the rainy season from August to November.

 Etymology:— The specific epithet “nigricans” refers to the dark color of flowers.

Sahut Chantanaorrapint and Kitichate Sridith. 2015. Thismia nigricans Chantanaorr. & Sridith, A New Species of Thismiaceae from Southern Thailand.
Phytotaxa. 217 (3): 293–297. DOI: 10.11646/phytotaxa.217.3.7