Wednesday, September 12, 2018

[Botany • 2018] Thismia aurantiaca (section Rodwaya, Thismiaceae) • First Record of the Family from Andaman and Nicobar Islands, India with A New Species

Thismia aurantiaca  Hareesh & M.Sabu

in Hareesh, Alappatt & Sabu, 2018

 Thismia is a mycoheterotrophic genus in the family Thismiaceae. We report a new family record for Andaman and Nicobar Islands and a new species for India. A detailed description along with conservation assessment, colour photos, distribution map, and key to the species from India are provided.

Keywords: Andaman Islands; Rodwaya; Thismia; Thismiaceae; new record; new species


Thismia aurantiaca Hareesh & M.Sabu, sp. nov. 

This species is similar to T. rodwayi but differs from the latter in having outer perianth lobes 5 times larger than inner perianth lobes (vs sub-equal), broadly triangular recurved outer perianth lobes (vs spathulate, up-curved) and inner perianth lobes with minute 0.5 mm long, erect mitre (vs well developed more than 1 mm long, bent and inter locking mitre).

 Type: M. Sabu & V.S. Hareesh 152774 (holo CALI; iso CAL, PBL), India, Andaman Islands, South Andaman, Mount Harriet National Park, elevation ± 320 m, 7 Aug. 2017. 

Etymology. The name ‘aurantiaca’ denotes the orange coloured flower of the plant.

Fig. 1 Thismia aurantiaca Hareesh & M.Sabu.
 a–b. Plant in habitat; c–e. habit (M. Sabu & V.S. Hareesh 152774).
 — Scale bar = 2 cm.
 — Photos by M. Sabu & V.S. Hareesh.

Fig. 2 Thismia aurantiaca Hareesh & M.Sabu floral parts.
 a. Habit showing split-opened flower with stamens; b– c. mitre; d. hypanthium side view; e. hypanthium front view; f–i. outer tepals; f–g. adaxial view; h–i. abaxial view; j– k. ovary with stigma (M. Sabu & V.S. Hareesh 152774).
 — Scale bars: a = 1 cm; b– c = 5 mm; d–e = 3 mm; f– k = 1 mm.
 — Photos by M. Sabu & V.S. Hareesh.

Habitat & Ecology — So far, we could observe three populations with around 18 individuals each in the evergreen forest patches of Mount Harriet National Park, South Andaman. The plants are growing in a damp habitat in the understory of evergreen forest in association with Amomum andamanicum V.P.Thomas, Dan & M.Sabu (Zingiberaceae), Dipterocarpus sp. and Hopea sp. (Dipterocarpaceae), Phrynium sp. (Marantaceae), Malaxis sp. (Orchidaceae). 

V.S. Hareesh, J.P. Alappatt and M. Sabu. 2018. Thismia aurantiaca sp. nov. (section Rodwaya, Thismiaceae): First Record of the Family from Andaman and Nicobar Islands, India with A New Species.  Blumea - Biodiversity, Evolution and Biogeography of Plants. DOI:  10.3767/blumea.2018.63.02.08