Perlis fairy lantern (Thismia perlisensis) resembling Thismia arachnites Ridley and Thismia javanica J.J.Sm.

NEWS - Perlis fairy lantern (Thismia perlisensis Besi & Rusea sp. nov.) was discovered during a scientific expedition in a wetland forest at the foot of a limestone hill, Perlis State Park, resembling Thismia arachnites Ridley (1905) and Thismia javanica J.J.Sm. (1910), but has a prominent reddish dome-shaped annulus.

Thismia perlisensis can be easily distinguished from T. arachnites and T. javanica by its blood-red dome-shaped annulus (vs. ring-like with a rim, orange annulus), prominent trilobed stigma with bifid and subulate lobes 1.8 mm long (vs. oblong, truncated stigma), and claviform apex of inner tepal appendage (vs. subulate apex of inner tepal appendage).

Stenoendemic to northern Peninsular Malaysia, Perlis State and possibly Langkawi Island. Although there have been sightings of the plant on Langkawi Island, this location is based solely on photos posted on social media. There are currently no specimens or additional information to confirm.

The new species grows in moist sandy soil in wetland forest, under the shade of fan palms, Licuala peltata, Donax canniformis, and Eugeissona tristis at an elevation of 100 meters. Flowering occurs in October. Diptera are seen trapped inside the flower tubes. This supports previous reports that Diptera frequently visit Thismia flowers.

T. perlisensis was found at the type site with minimal human activity that helps protect the habitat. However, as a holomycoheterotrophic species, its cryptic growth habit and short flowering period make it difficult to estimate mature individuals.

Little is known about its habitat, ecological preferences, and population structure. The researchers propose the current conservation status of T. perlisensis as Data Deficient (DD). Further research and monitoring of this species is strongly recommended.

DESCRIPTION

Herb achlorophyllous, small, terrestrial, ca. 5 cm tall. Roots clustered, horizontal, vermiform, fleshy, light brown tinged with white.

Stem 1 cm long, erect-ascending, unbranched, 1–1.5 mm in diameter, white, glabrous.

Leaves 4, white, appressed, clasping stem, narrowly triangular with acute apex, scale-like, 3–6 mm long, 0.9–2 mm wide; basal leaves smallest, upper leaves (almost equivalent to floral bracts) largest.

Floral bracts oblong-triangular, entire, acute, ca. 1 cm long, 2 mm wide, pale brown.

Pedicel 2–3 mm long, white.

Inflorescence flowers solitary, actinomorphic, of six fused tepals, forming a floral tube with free apical tepals, ca. 3.5 cm long to the tip of the inner tepal appendage; white to dark red; floral tube (hypanthium) urceolate, ca. 1.2 cm in height, ca. 8.4 mm in width in the upper part, translucent; apex of floral tube fused to form a bright red, glossy, convex annulus, 0.8–1.0 mm wide, longitudinally grooved with 7 vertical ribs, reddish at upper part; outer surface white with ca. 12 vertical reddish streaks on the upper half of the ribs, verrucose, ribbed; inner surface reticulate, transverse bars present; outer tepals 3, ovate, apex obtuse to rounded, tongue-like, hangs down over the upper margin of the perianth tube, 2.3 mm long, 2 mm wide at base, white; inner tepals 3, erect, narrowly triangular, apices obtuse, ca. 3 mm long, ca. 0.9 mm wide at base, tapering from the proximal lower margin into a long, reddish to reddish white filiform appendages, ca. 2 cm long, ca. 0.4 mm in diameter, apices claviform, 3 mm long, 0.5 mm in diameter; annulus (apical part of the floral tube) blood red, rounded, ca. 7 mm wide, convex, raised ca. 2 mm in height, dome-shaped, without rim, connected with the inner tepals; upper surface glossy; aperture, ca. 1.2 mm in diameter, hexagonal; lower margin minutely rugose; stamens 6, reddish, pendent from the annulus, 3 mm long, 2.8 mm in diameter, individual stamen with 2 thecae, thecae ca. 0.8 mm long and 0.5 mm wide; filaments 6, reddish, 0.5–0.8 mm long with apertures 0.2 mm wide in between filaments; supraconnectives 6, ca. 2.6 mm long, laterally connate, forming a tube, glabrous on the outer surface, apices tridentate with an indistinct and fragile hair on the free margins, with a triangular to quadrangular lateral appendages, upcurved; interstaminal glands, rounded, on the line of fusion between each connective; pistil ca. 2–2.3 mm long, white; style ca. 0.8 mm long, cylindrical, slender, erect, glabrous; stigma ca. 1–1.5 mm long, up to 1.8 mm long when the lobes straightened, glabrous, 3-lobed; lobes bifid, narrowly triangular or subulate, apices acute, lobes apices curved inward, white; ovary inferior, cup-shaped or obconical, ca. 2 mm long.

Original research

Edward Entalai Besi, Qistina Anis Mad Jabar, Syamil Abd Rahman, Mohd Zulkifly Saad, Ag Shaffie Ag Ahmadni & Rusea Go (2024). Thismia perlisensis (Thismiaceae), a new red-annulus Thismia species from Peninsular Malaysia. Phytotaxa 675 (1): 001–010, DOI:10.11646/phytotaxa.675.1.1

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