Thismia aliasii Siti-Munirah, 2025

Thismia aliasii Siti-Munirah sp. nov.

Figs 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6

Diagnosis.

Thismia aliasii is very similar to the species of the T. subsection Odoardoa , as the tepals are the same in shape and size. However, the tepal appendages of the new species are of unequal length, the inner ones are longer than the outer ones, while the tepal appendages of the other species are of equal length. In addition, in the new species the margins of the individual connectives are raised abaxially into the conspicuous rib, whereas connectives are almost flat abaxially in the rest of the species.

Type.

Malaysia. • Peninsular Malaysia: Terengganu, Hulu Terengganu District, Hutan Simpan Pasir Raja, Chemerong Forest Eco Park , Gunung Chemerong , 4°39'33.2"N, 102°58'58.6"E, elev. ca 640 m, 26 July 2023, Siti-Munirah, FRI 79119 (holotype KEP!, spirit collection, barcode no. SC 13201 ) GoogleMaps .

Description.

Achlorophyllous herb, up to ca. 11 cm tall, mostly glabrous (where not stated otherwise). Roots vermiform, unbranched, ca. 1.5 mm in diameter, light brown. Stem erect, up to 56 mm long, 1.8–2 mm in diameter, white-cream to light brown, bearing 1–2 flowers. Leaves up to 5, spirally arranged (arranged denser at stem base and looser at apex), triangular to narrowly triangular (shorter at stem base and longer and narrower at stem apex), scale-like, apex pointed, margin almost entire to slightly irregularly serrate, up to 7 mm long, ca. 2 mm wide at base, colored similar to stem. Flowers terminal and solitary, or in 2 - flowered terminal inflorescence, actinomorphic, ca. 58 mm long (including ovary, floral tube, tepals and tepal appendages when erected). Involucral bracts 3, similar to upper leaves, triangular to narrowly triangular, scale-like, acute, with entire margin, 8 mm long, ca. 2.5 mm wide at base, white-brownish / light brown. Pedicel to 1.5 mm long at anthesis, to ca. 4 mm long after anthesis, white-brownish. Floral tube obovoid funnel-shaped, 20 mm long, ca. 4 mm wide at base, ca. 8 mm wide at middle, ca. 10 mm wide distally; outer surface with minute glands, orange to sepia-brown, with 12 darker longitudinal ribs; inner surface smooth or rough, almost similar color to the outer surface, with transverse bars. Tepals 6, free, spreading, triangular, apex acute, 7 mm long, ca. 1–1.5 mm wide (ca. 1.5 mm at base), smooth, color similar to flower tube (dark brown at apex, yellow-orange at back), each apically bearing a tentacle-like appendage 0.5 mm wide and narrowing towards the apex; appendage of outer tepal up to 3.5 mm long, dark brown; appendage of inner tepal ca. 26–32 mm long, brownish. Annulus moderately raised, hexagonal in outline, ca. 6 mm in diameter, with ring width ca 1.5 mm, brown-orange, aperture ca. 3 mm in diameter. Stamens 6, pendulous from annulus; filaments laterally pale orange, otherwise translucent white; connectives broad and flattened, fused laterally into a tube, shortly papillose, translucent white, with hairs around thecae, with margins abaxially raised to form conspicuous ribs along the sutures between the connectives, ribs distally slightly protruding beyond the apex of supraconnective; interstaminal glands conspicuous, placed between bases of lateral appendages; supraconnective with 3 filiform apical appendages (central appendage ca. 2 mm long and paired appendages ca. 2.4 mm long) and with 2 acute hook-like subapical appendages ca. 0.6 mm long positioned adaxially between the apical appendages and the lateral appendage; lateral appendage skirt-like, projecting towards the floral tube and not reaching the supraconnective apex, translucent white and brown on sides, lateral margin wavy. Ovary red, pale cream proximally and blackish distally; unilocular; placentas 3, free, column-like, arising at ovary base; ovules numerous. Style dark blackish-orange, ca. 1.2 mm long; stigma ca. 1.4 mm long, papillose, 3 - lobed, erect, lobes ± rectangular, bifurcate at the apex, black-greenish. Fruit dehiscent, cup-shaped, ca. 6 mm high, ca. 7 mm in diameter, pale brownish, darker in the upper part. Seeds long fusiform ca. 0.75 mm long, ca. 0.25 mm wide.

Additional specimens examined.

Malaysia. • Peninsular Malaysia: Terengganu, Hulu Terengganu District, Pasir Raja FR, Chemerong Forest Eco Park , Gunung Chemerong , elev. ca 642 m, 3 October 2019, Mohamad Alias, FRI 91119 ( KEP spirit collection, barcode no. SC 13202 ) ; elev. ca 640 m, 26 July 2023, Siti-Munirah, FRI 79167 ( KEP spirit collection, barcode no. SC 13203 ) .

Distribution.

Endemic to Terengganu, Peninsular Malaysia. Currently only known from the type locality, Gunung Chemerong (Figs 2 View Figure 2 , 3 View Figure 3 , 7 View Figure 7 ).

Ecology.

The species inhabits moist shady areas of upper hill dipterocarp forest on moist soil at elevation of 640 m a. s. l. Flowering and fruiting recorded in July and October. The population was found in moist, shaded areas next to the main hiking trail to the summit of Gunung Chemerong Berembun Langsir at altitudes of 640 m above sea level. The species was found a few hundred meters away from the main river.

Etymology.

The species is named after Mr. Alias (the second author), a current ranger of the Terengganu Forestry Department ( JPNT), who is also a freelance photographer (known as John Sp) and who was the first to discover the species.

Conservation status.

Since 2019, several surveys have been conducted at an area of 4 hectares, but the species was observed only twice, with a total of 5 individuals recorded. The main threat to the population is the degradation of habitat quality due to hiking activities, as the population is found near the main hiking trail which is heavily used by hikers ascending to the summits of Gunung Chemerong Berembun Langsir. Therefore, according to IUCN Red List (IUCN 2024) this species is assessed as Critically Endangered, CR B 2 ab (iii), D. More surveys are needed to determine the population size of the species.

Notes.

Thismia aliasii is easily recognized within the genus by the combination of the following characters: vermiform roots, almost uniform flower coloration (light to dark orange to sepia-brownish red), inner tepals free from each other, unequal tepal appendages (appendages of the outer tepals being shorter than those of the inner tepals), stamens each with 3 long filiform apical appendages, 2 acute subapical appendages and a lateral appendage, and connectives laterally thickened into conspicuous abaxial interstaminal ribs. Within the infrageneric classification of Kumar et al. (2017), T. aliasii is assigned here to Thismia subgenus Thismia section Thismia subsection Odoardoa Schltr., as long as it has free tepals equal in shape and size. The new species probably belongs to clade 5 defined by Shepeleva et al. (2020), which is characterized by free inner tepals and the presence of appendages of the outer and inner tepals. In addition, the fact that the appendages of the inner tepals are much longer than those of the outer tepals make T. aliasii similar to T. neptunis Becc. , (Sochor at al. 2018), which belongs to T. subgen. Thismia sect. Thismia subsect. Brunonithismia Jonker according to Kumar et al. (2017), but was recovered as a member of clade 5 by Shepeleva et al. (2020).

The connectives of most Thismia species are usually flat and without any processes abaxially, making T. aliasii unique not only among T. subsect. Odoardoa but within the entire genus. The only other exceptions are species from T. sect. Geomitra (Becc.) Kumar & S. W. Gale which have ribs in the center of each stamen but differ by coralliform roots and flower mitre.

We summarize Thismia subsect. Odoardoa to comprise 23 species based on the above-mentioned characteristics and following the classifications of Kumar et al. (2017) and Shepeleva et al. (2020) with additions from Chantanaorrapint et al. (2016), Hroneš et al. (2018), Nishioka et al. (2018), Dančák et al. (2020), Siti-Munirah and Dome (2019), Siti-Munirah et al. (2024), Ya et al. (2024):