Thismia domei M.Y.Siti-Munirah, 2019

Yunoh, Siti-Munirah Mat & Nikong, Dome, 2019, Thismia domei and T. terengganuensis (Thismiaceae), two new species, and T. javanica, a new record from Terengganu, Peninsular Malaysia, PhytoKeys 124, pp. 123-137 : 125-126

Thismia domei M.Y.Siti-Munirah sp. nov. Figures 1 , 2 , 3

Diagnosis.

The whole plant is completely white translucent and the flower is strigose with white trichomes covering the outer surface of the perianth tube and ovary; the apex of the perianth tube is partially covered by the apical part of flower tube with a ring-like annulus and together with six perianth lobes are upright and curve inwards with a dorsal long appendage on each lobe.

Type.

MALAYSIA. Peninsular Malaysia: Terengganu, Kuala Berang District, Hulu Telemong Forest Reserve, ca 207 m alt., 22 Nov 2018, Dome Nikong, FRI 91111 (holotype KEP!).

Description.

Terrestrial, achlorophyllous, whitish herb to 9 cm tall. Roots vermiform brownish with white apices. Stems erect (sometimes curved), unbranched, 0.2 to 2.5 cm long, glabrous with ridges. Leaves scale-like, appressed, 2-7 mm long, 2 mm wide, smaller at the base leaf increasing in size above, alternate, single, triangular to lanceolate, translucent white, apex acute or acuminate, base appressed. Internodes 4-10 mm. Involucral bracts 3, translucent white, ca. 1-1.2 cm long, lanceolate, apex acute to acuminate, margin entire, base appressed, with a central vein. Bud to 7 mm long, pale to dark purple. Pedicel 4-5 mm long. Flowers solitary to 7-8 cm long (including appendages); perianth lobes 6, each 3 × 2 mm (excluding appendage), obovate to spathulate are upright and curve inwards over perianth chamber, apex truncate, with erect subulate appendage abaxially, ca. 3.5-5.5 cm long, ca. 0.5 mm wide, cylindric, apex rounded or falcate; perianth tube bowl-like, 5-5.5 mm long, 3-6 mm wide, narrowed just above the ovary, widest just below the lobes, white translucent, outer surface with longitudinal ribs covered with numerous white translucent thick trichomes; apical part of perianth tube with annulus and opening circular aperture ca. 2 mm in diameter, from above ring-like, whitish, glabrous, Stamens 6, pendulous attached to the inner wall of perianth tube, ca. 2.5 mm long, apex lobed with 3 apical appendages with glandular tip (visible in fresh plant); filaments short, free, white, each with two rounded oblong thecae facing the inner wall of the perianth tube; anthers oblong, 2 mm long; lateral appendage box-shaped; ovary inferior, cup-shaped, ca. 4 mm long, whitish to brownish, outer surface smooth, without longitudinal ribs, covered with numerous white translucent thick trichomes, unilocular with 3 parietal placentas; style ca. 0.5 mm long; stigmas 3, ca. 0.6 mm long, oblong, papillate, 3-lobed, lobes slightly folded, apex truncate. Fruit cup-shaped, translucent white.

Distribution.

Endemic in Peninsular Malaysia, Terengganu. Currently known only from the type collection.

Ecology.

In lowland dipterocarp forest on wet, moist soil in shade at an altitude of 207 m. Flowering in November-December. This new species was encountered on bamboo leaf litter near an elephant trail. When mature T. domei produces an unpleasant smell like rotting fish.

Etymology.

The species is named after Mr Dome Nikong, professional photographer and freelance researcher, who first discovered this species and the other new species described below as well as T. javanica .

Conservation status.

Critically Endangered (B2 ab(iii)). Following the 2012 IUCN Red List Categories and Criteria, (IUCN 2012), this species is assessed as critically endangered because it is only known from the type locality. It is very rare. Fewer than 10 individuals were observed, which included both flowering and fruiting individuals. The type locality is within a forest reserve in disturbed forest area near the river bank at an elevation of c. 207 m. The species is under threat because selective logging activities are currently on-going within the forest reserve.

Notes.

Thismia domei , based on colour, is most like T. clavarioides K.Thiele ( Thiele and Jordan 2002) and Thismia taiwanensis S.-Z. Yang, R. M. K. Saunders & C.-J. Hsu, ( Yang et al. 2002). Both have completely white perianth lobes that are upright and curved inwards towards the perianth tube with an appendage on each lobe. However, T. domei differs from these species in that its perianth tube is fully covered with thick trichomes and it has six perianth lobes each with an appendage as opposed to being completely glabrous and T. taiwanensis from Taiwan has only three perianth lobes with appendages and the perianth of T. clavarioides forms a mitre from Australia. T. domei is unusual in its conspicuous cell inclusion white spot which appear to be aleurone grains.

Figures

Figure 1. Thismia domei Siti-Munirah A habit (A 1 roots A 2 tip of filiform appendages), B top view of plant C perianth tube covered with trichomes (C 1 trichome C 2 white spots D top view of flower showing perianth lobes overlapping and appendages on the each lobes forming loose mitre E top perianth tube covered with apical part of flower tube and annulus F longitudinal section of flower (F 1 base perianth tube and ovary) G perianth lobes from outside H perianth lobes from inside I pendulous stamen attached to the inner wall of perianth tube (abaxial view of stamens) J pendulous stamen attached to the inner wall of perianth tube (adaxial view of stamens) (J 1 stamen from side view J 2 three appendages at apical margin) K ovary showing stigma (K 1 ovary). Photo credit: A, A 1, B, C, C 1, D, F, G, H, J, J 1, J 2, K Dome Nikong; A 2, C 2, E, F 1, I, K 1 Siti-Munirah MY.

Figure 2. Thismia domei Siti-Munirah A, B habit of two plants C leaf D bract E perianth lobes from top F top view of apical part of perianth tube with annulus G inner adaxial view of six pendulous stamens H stamen attached to perianth tube I a perianth lobe with perianth tube from side view J ovary with stigma and placenta (below). All from Dome Nikong FRI 91111. Drawn by M. Aidil. The drawing is based on spirit material.

Figure 3. Thismia domei. A, B habitat on leaf litter within a bamboo clump (plant indicated by red arrow) C habit of the flowering T. domei D Mr Dome Nikong showing T. domei at different stages of anthesis E habit of T. domei. Photo credit: Dome Nikong.