Thottea beungongtanoeh Mustaqim

Mustaqim, Wendy A. & Arico, Zulfan, 2022, Thottea beungongtanoeh (Aristolochiaceae), a new species Irom Aceh, northern Sumatra, Taiwania 67 (4), pp. 587-590 : 587-589

Thottea beungongtanoeh Mustaqim , sp. nov. Fig. 1.

Type: INDONESIA. Aceh Province, Aceh Timur Regency , Bireum Bayeun Subdistrict , Alue Nyamuk Village , 4°31'18.9"N 97°51'07.5"E, 80 m asl, 22 June 2022, Mustaqim & Arico RSG8 (Holotype: ANDA).

Diagnosis: Thottea beungongtanoeh can be recognized from other species in the genus by the 33- lobed style. It is similar to T. grandiflora Rottb. , besides having more numerous style lobes (33 vs 20), this species differs in having inflorescence close to ground level (vs not from the ground level) and tubular perianth tube (vs campanulate).

Perennial subshrubs, to c. 1.5 m tall. Stem ascending to erect, with horizontal apex, scarcely branched, terete, pubescent; node swollen, constricted above nodes. Leaves alternate, distichous; lamina chartaceous; obovate, the lower 1-2 usually elliptic or narrowly elliptic and distinctly smaller, 15.2-21.5 × 6.3-10.6 cm, base cuneate, apex shortly acuminate, margin entire, adaxially green, scabrous, abaxially pale green, patent-pubescent, midvein slightly prominent adaxially, distinctly raised abaxially, lateral veins 7-9 on each side of the midrib; petioles 4-6 mm long, densely covered with patent hairs. Inflorescences 1-2 arising from near the base of the stem, close or at the same with ground level, solitary to 3- flowered; peduncle c. 2 cm long, patent-pubescent, rachis c. 1.5 cm long, patently pubescent; bracts beef red, elliptic, 5-7 × 3-3.5 mm, apex obtuse, adaxially patently pubescent, abaxially glabrous, persistent after anthesis. Pedicels and ovary c. 1.7 cm long, longitudinally ribbed, patently pubescent. Perianth burgundy, tube ellipsoid,

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Mustaqim & Arico: Thottea beungongtanoeh (Aristolochiaceae) , a new species from Sumatra 2.5-2.7 × 1.5 cm, base shallowly cordate; verrucose and glabrous inside; longitudinal veins and veinlets prominent outside, patently pubescent; perianth lobes shallow, broadly half-circular, 0.6-0.8 × 3.8-4.2 cm, apex emarginate, verrucose and glabrous inside, outer surfaces with prominent veins and veinlets, patently pubescent. Stamens 46 in two rows, the lower whorl 27, the upper whorl 19, filaments creamy white, c. 1 mm long, glabrous, connective creamy white, apex rounded, tip reddish, anthers extrorse, yellow, narrowly oblong, lower whorls c. 2 mm long, upper whorls 1.8 mm long. Style column cylindric, c. 2.5 mm long, glabrous except the pubescent apex, lobes 33, 8 facing upward, the rest radiate, positioned c. 0.75 mm higher than stamens. Capsules (immature) fusiform, longitudinally ribbed, reddish brown, covered in coarse hairs.

Phenology: Flowering and fruiting in June.

Distribution and Ecology: Indonesia, endemic to northern Sumatra (Aceh Province), only known from the type locality (Fig. 2). Found in the lowland mixed dipterocarp forests on undulating terrain at the elevation around 60-80 m asl, on clay mixed with humus soils.

Etymology: The specific epithet is derived from the Acehnese Language, beungong tanoeh, which means ̒flower of the ground̕, indicating the position of the flowers.

Preliminary conservation status assessment: Critically Endangered. Only known from the type locality, all individuals (around 15) were found in lowland and unprotected forests threatened by conversion into agricultural fields and plantations. Although forests around the type locality, with very similar landscape and vegetation, is poorly explored, we considered that the species should be placed as being threatened. Following IUCN (2012) and IUCN Standards and Petitions Committee (2022), this species is best tentatively assigned as Critically Endangered as having AOO <10 km 2, known only from one location, and available habitat is declining and mature individuals less than 50 (CR B2ab(iii), D).

Notes: The number of stamens and style lobes of this species is among the highest within the genus. The number of stamens, i.e. 46, so far only known from T. grandiflora Rott. (1783) , a species known from Myanmar to Peninsular Malaysia and Singapore, characterized by having larger campanulate flowers ( Hou, 1984). Furthermore, the number of style lobes with 33 is by far the most numerous in the genus. The highest number of style lobes in this genus had been known to be 20 in T. grandiflora and T. macrophylla Becc. ( Hou, 1984; Huang et al., 2003; Yao et al., 2015).

To facilitate identification, an amendment to the couplet from the recently published key for the species of Thottea in Sumatra ( Mustaqim and Putra, 2020) is provided here:

4a. Perianth obscurely lobed or lobed to less than 1/3 halfway down. 4̕

4b. Perianth distinctly lobed, divided halfway or deeper ..................... 5

4̕a. Style lobes 33; perianth distinctly lobed .... ... .. T. beungongtanoeh

4̕b. Style lobes c. 10; perianth obscurely lobed ................ T. beccarii