Begonia tripurensis Dixit, B.Datta & D.Borah

Bora, Dixit, Borah, Dipankar, Hughes, Mark, Das, Sani, Banik, Biplab, Debbarma, Smita & Datta, Badal Kumar, 2024, Begonia tripurensis (Begoniaceae, sect. Platycentrum), a new species from Tripura, Northeast India, Phytotaxa 640 (2), pp. 177-182 : 178-180

Begonia tripurensis Dixit, B.Datta & D.Borah sp. nov.

Type:― INDIA . Tripura: Gomati, Near Dumboor Lake , N 23° 25’ 34.97”, E 91° 49’ 09.042”, 115 m a.s.l, 10 January 2023, Dixit Bora & Sani Das 4315 (holotype CAL!; isotype ASSAM!) .

Diagnosis:― Begonia tripurensis is similar to B. scintillans Dunn (1920:111) in its rhizomatous habit, villous rhizome, stipules hairy abaxially, lamina ovate with reddish hairs on the lower side, inflorescence axillary, staminate flower with four tepals, capsules with three wings with central one larger, but B. tripurensis differs chiefly in being larger at 20–30 cm tall (vs. 7–15 cm), having deciduous stipules 2–2.1 × 0.7–0.8 cm, abaxial side with red stiff hairs (vs. persistent stipules, 6–11 × 4–6 mm, villose abaxially), lower surface of lamina dense reddish hirsute (vs. lower surface red tomentose), outer tepals of staminate flower with acute apex (vs. rounded), capsule with red stiff hairs (vs. red villose hairs), apex of longest wing acuminate, size 15–17 × 5–6 mm (vs. apex rounded, size 5 × 4–6 mm). It is also similar to B. chindwinensis (Maw et al., 2021: 226) and B. thomsonii , for which a comparison table is provided below ( Table 1 ).

Monoecious rhizomatous herb, perennial, creeping, 20–30 cm high. Rhizomes short, 3–4 × 1–1.5 cm, internodes 1–1.5 cm on the rhizome, erect stems only seen during flowering, elongating to ca. 10 cm on flowering internodes, reddish, minutely villous. Stipules narrowly triangular, 20–21 × 7–8 mm, adaxial side sub-glabrous, abaxial side with dense transparent hirsute. Leaves 6 or 7; petiole 10–12 × 0.5–0.7 cm, densely pilose; lamina 7–10 × 4–8 cm, ovate to broadly ovate, basifixed, base cordate, basal lobes overlapping when young, becoming non-overlapping when mature, asymmetric, adaxially sparsely pilose, light green, abaxially densely reddish hirsute; venation basally palmate 8–9, prominently raised on upper surface; margin repand to serrate, ciliate; apex acute to attenuate. Cymes axillary, few, sub-pendulous, pilose, primary peduncle 5–10 cm long, secondary 1–3 cm long. Bracts caducous, subulate, 2–3 × 1–2 mm, hirsute. Staminate flowers 5–7, pedicel 1.5–2 cm long, pubescent, tepals 4, white to pink, outer tepals broadly ovate to orbicular, 10–12 × 10–11 mm, pinkish hirsute on the outer surface, apex acute, inner 2 tepals elliptic to ovate, 5–8 × 2–3 mm, glabrous, apex obtuse; stamens 40–60, ca. 2 mm long, sub-equal, anthers obovate, apex emarginate, basifixed, lower anthers sub-sessile, central anthers on a filament up to 2 mm long. Pistillate flowers 2 or 3, pedicel 1–1.2 cm long; tepals 5, pinkish-white, 4 outermost sub-equal, hirsute on the outer surface, ovate, 9–10 × 4–5 mm, inner one smaller, glabrous, elliptic to ovate, 6–7 × 3–4 mm, apex rounded; ovary 5–7 × 8–10 mm excluding wings, reddish, sparsely hirsute locules 2; styles 2, 5–7 mm long, fused at the base, spiraled; wings 3, adaxial wing oblong, 6–8 × 3–5 mm, apex acuminate, lateral wings 2, underdeveloped. Capsule sub-pendulous, 15–17 × 12–14 mm, adaxial wing larger 15–20 × 5–6 mm, lateral wings 2, 2–3 × 5–6 mm.

Flowering and Fruiting:― January March

Habitat and ecology:― The plants were found on a cliff, with a total of four sub populations of 8–15 individuals separated by at least 300 meters. They were found growing with Lycopodiella cernua (L.) Pic.Serm., Oplismenus hirtellus (L.) P.Beauv., Lygodium flexuosum (L.) Sw., Thysanolaena latifolia (Roxb. ex Hornem.) Honda , Colocasia sp. , etc.

Distribution:― Only known from India (Tirthamukh, Gomati district, Tripura).

Etymology:― The specific epithet refers to the state Tripura, in North East India from where the plants of type specimen were collected.

Additional specimens examined (paratypes):― INDIA . Tripura: Gomati, Near Dumboor Lake , N 23° 25’ 28.52”, E 91° 49’ 19.99”, 121 m a.s.l, 20 January 2023, Dixit Bora & Sani Das 4320 ; ibid., N 23° 25’ 34.56”, E 91° 49’ 09.10”, 119 m a.s.l., 25th March 2023, Dixit Bora & Sani Das 4321 (Herbarium of Tripura University) ; ibid., N 23° 25’ 32.18”, E 91° 49’ 02.56”, 112 m a.s.l., 20th May 2023, Dixit Bora & Sani Das 4322 (Herbarium of Tripura University) .

Conservation status:― After several investigations throughout the Gomati district of Tripura, only four populations each with 8–15 individuals were found within a 500 meter area. However, the similar habitats exist in other regions of the state where the species may occur. In view of the limited fieldwork presently possible, an assessment of Data Deficient (DD) is suitable for this species due to lack of knowledge on its full distribution ( IUCN Standards and Petitions Committee, 2022).

Tables

TABLE 1. Comparison of key morphological characters of Begonia tripurensis, B. scintillans, B. chindwinensis and B. thomsonii.

	B. tripurensis	B. chindwinensis	B. scintillans	B. thomsonii
Rhizome and stem	Villous, erect stem present during flowering	Finely pubescent, erect stem absent	Villous, erect stem absent	Villous, erect stem present during flowering
Stipule	Deciduous, elongate triangular, abaxial side dense transparent hirsute	Deciduous, triangular, abaxially rusty villous	Persistent, lanceolate, abaxial side villous	Persistent, lanceolate, abaxial side villous
Petiole	Petiole dense whitish villous	Petiole dense rusty villous	Petiole red vilous	Petiole dense red villous
Leaf	Ovate to broadly obovate	Widely suborbicular	Ovate-orbicular	Ovate to orbicular
Upper surface	Sparsely pilose, light green	Extremely sparsely short setulose	Densely pale strigose, dark green sometimes with silver variegation	Dark red to green, densely red strigose
Lower surface	Pale green, dense reddish hirsute hairs	Pale green, densely red strigose	Pale green or red, red tomentose	Pale green to purple, red strigose
Staminate flower	White to pink, outer tepals pinkish hirsute, apex acute	White to pink, outer tepals red hirsute-villous, apex rounded	Coral pink, outer tepals pilose, apex acute	Pale pink to pink, outer tepals red villous, apex rounded
Pistillate flower	Tepals five, styles two, ovary two-locular	Tepals five to six, styles two, ovary two-locular	Tepals four to five, styles three, ovary three-locular	Tepals five to six, styles two, ovary twolocular
Capsule	Reddish hirsute, larger wing ca. 2 cm long, apex acuminate	Red villous, larger wing ca 0.7 cm long, apex rounded	Red villous, larger wing ca 0.5 cm long, apex rounded	Sparsely villous, larger wing 1.2 – 3.0 cm long, apex rounded