Thursday, March 9, 2023

[Botany • 2023] Thismia kenyirensis (Thismiaceae) • A New Species from Taman Negeri Kenyir, Terengganu, Peninsular Malaysia

Thismia kenyirensis  Siti-Munirah & Dome, 

in Siti-Munirah & Dome, 2023.

A new mycoheterotrophic species, Thismia kenyirensis Siti-Munirah & Dome from Peninsular Malaysia, is described and illustrated. Thismia kenyirensis differs from other previously described species in the following characteristics: the flower tube is completely orange, with alternating darker and paler-coloured longitudinal lines on the outer and inner surfaces, the outer tepals are ovate (petaloid), the inner tepals are narrowly lanceolate, each ending with a long appendage. According to the IUCN Red List categories and criteria, T. kenyirensis is provisionally classified as Least Concern.

Keywords: Brunonithismia, lowland dipterocarp forest, rare species

Thismia kenyirensis
A plant with flower and roots B top view of flower showing tepals C top view of ovary and stigma D stamen (i, side view; ii, inner view) E outer view of three pendulous stamens F longitudinal section of ovary G style and stigma H bract I leaf.
All from FRI91122a (spirit material). 
Drawings by Mohamad Aidil Noordin.

Thismia kenyirensis
A mature plant with flowers and roots, scale in centimetres (cm) (FRI91122b) B mature plant in natural habitat (FRI91122a) C vermiform roots (FRI91122c) D young flower with mature ovary and stigma (FRI91122c).
Photos by Siti-Munirah MY (A); Dome Nikong (B–D).

Thismia kenyirensis
A bracts with ovary and pistil, lateral view B top view of stigma C flower, side view D longitudinal section of floral tube and stamens E flower, top view F annulus G stamens, outer view.
Photos by Siti-Munirah MY (A–C, E, F; All from FRI 91122b); Dome Nikong (D, G; No specimens).

 Thismia kenyirensis Siti-Munirah & Dome, sp. nov.
Diagnosis: Distantly similar to Thismia hongkongensis Mar & Saunders but differs by petaloid, ovate outer tepals which are ca. 8 mm long, narrowly lanceolate-linear, ca. 8 mm long inner tepals which are not forming a lose-dome, up to 28 mm long appendages of inner tepals, orange floral tube, which lacks reticulate pattern on its inner surface and connective apex with 3 long appendages.

Distribution: Endemic to Terengganu, Peninsular Malaysia. Currently, the occurrence is only from the type locality, Sungai Cendana area (Map 1). In addition, T. kenyirensis was observed in two other populations in the vicinity of Tasik Kenyir. It was sighted near Sungai Saok and on the way to Gunung Gagau (Wong Pui May personal communication), both in the Tasik Kenyir region. However, there are still no specimens and GPS information to verify these findings. This means that only the occurrence of the population in Sungai Cendana has been confirmed.

Ecology: In moist shady areas of lowland dipterocarp forest on moist soil at elevations of 150–220 m a.s.l. Flowering and fruiting mostly from September to April, but also recorded to flower in June. Historically, the type locality was botanized as early as 2007. Based on the results of Lim et al. (2008), T. alba was also recorded during the survey in the Sungai Cendana area. This is in contrast to T. kenyirensis, which was not mentioned, implying that it was not seen or collected at that time. During our recent visit, we were also able to find T. alba not far from the original population of T. kenyirensis.

Etymology: The epithet refers to Lake Kenyir, Kenyir State Park (Taman Negeri Kenyir), where the species was found.

 Mat Yunoh Siti-Munirah and Nikong Dome. 2023. Thismia kenyirensis (Thismiaceae), A New Species from Taman Negeri Kenyir, Terengganu, Peninsular Malaysia. PhytoKeys. 221: 61-72. DOI:  10.3897/phytokeys.221.98571