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Begonia kapuashuluensis Randi & Ardi, sp. nov., B. sect. Petermannia (Fig. 1). Type: ��� INDONESIA, West Kalimantan Province, Kapuas Hulu Regency, Boyan Tanjung District, 0��20'44.84"N, 112��25'4.53"E, 110 m elev., 10 July 2017, A . Randi AR-1022 (holotype BO!). Diagnosis:��� It is allied to B. darthvaderiana C.W.Lin & C.I Peng (Lin et al. 2014: 132) in habit and floral characters, but differs in being a smaller plant up to 20 cm (vs. 25���70 cm) height with smaller leaves 9���14 �� 4���7 cm (vs. 13���22 �� 8���13 cm), deep bluish green (vs. blackish green with a narrow pale margin) leaves, and more stamens (22���31 vs. 7���11). A small herb, erect, up to 20 cm tall. Stem with 1���3 branches, 4���7 mm in diameter at the base, glabrous, bright red to brownish, fleshy and succulent, internodes 1���3 cm apart. Stipules caducous, asymmetric, translucent, glabrous, elliptic to lanceolate, 10���15 �� 3���5 mm, with a stiff main rib and many parallel red veins; margin entire, apex acute with a short-pointed tip; pale green to red to brownish. Leaves 4���7, simple, alternate, oblique, glabrous; petiole 1���4 cm long, red to brownish, glabrous; lamina ovate, 9���14 �� 4���7 cm (basal lobes included); strongly asymmetric with a well-developed basal lobe on one side giving a cordate appearance, base unequal, basal lobes 1���3 cm long, margins minutely denticulate, generally with a narrow dark red border adaxially that is clearly visible on young leaves, apex acuminate; adaxially shiny, deep bluish-green, surface flat or slightly bullate, abaxially light red to crimson, glabrous; venation palmate-pinnate, midrib distinguishable, with 3���4 lateral veins each side, other primary veins branching dichotomously; young leaf brownish abaxially. Inflorescence protogynous, terminally or axillary, erect, 6���12 cm long; basal branch with a pair (rarely 2 pairs) of pistillate flowers on short peduncle ca. 1 cm long, often with leaves at the first branch; upper distal to 10 cm long, zig-zag, branching cymosely, peduncle to 5 cm long, cymes branching to 3 orders, crimson to brownish, glabrous; bracts caducous, translucent, glabrous; bract on nodes of pistillate flower elliptic to lanceolate ca. 5 �� 1 mm, cream to pinkish, margin entire, apex acute to cuspidate; bracts on higher part of inflorescence similar but smaller. Staminate flower with 2 pink tepals, each tepal ovate to orbicular or obovate, 3���5 �� 3���5 mm, glabrous, margin entire, apex acute to rounded; pedicel pink to crimson, 2���5 mm long, glabrous; androecium symmetric with 22���31 yellow stamens, filament 0.6���1.2 mm long, anthers obovate 0.7���1.4 mm long, apex opened by slit. Pistillate flower 10���20 mm across, each flower blooming alternately; pedicel pink to brownish red, 4���8 mm long, ca. 1 mm in diameter, glabrous; ovary 3-locular, asymmetric, 7���11 �� 10���15 mm (wings included), yellowish-green in the middle, red to brownish on the wings; tepals 5, glabrous, 2 outer and 3 inner, all pink and elliptic, 6���8 �� 4���5 mm, apex acute to obtuse; styles 3, bifid, 2���4 mm long, golden yellow; stigmas narrowly Y-shaped, forming a papillose spiral band. Fruits nodding, 7���15 �� 10���18 mm (wings included), pink to crimson, glabrous; wings 3, subequal, nearly parallel but with rounded, apex acute or mucronate, 3���4 mm wide at the widest point. Distribution: ���Endemic to Borneo, widespread in the western part of the Muller Mountains that administratively belong to Kapuas Hulu Regency of West Kalimantan Province, Indonesia. Habitat: ���Humid areas near rivers or narrow valleys under a dense canopy of mixed dipterocarp forest at 100��� 300 m elev. Etymology: ���The epithet refers to the name of regency where this species was found, Kapuas Hulu. Provisional Conservation Status: ���Near threatened (NT) (IUCN, 2019). This species is observed in seven localities and locally abundant in the western part of Muller Mountains. Although based on EOO = 184.6 km �� and AOO = 28 km �� this species potentially qualifies for the endangered category, but we have observed that this species is growing in relatively undisturbed forest and in several protected forest areas. However, the populations could be threatened due to extraction by plant hunters to be sold as an ornamental, as this beautiful species is well known among Begonia enthusiasts. It has the popular trade name Begonia ���temuyuk��� and is for sale on commercial and social media sites for prices ranging from 50 US dollars to 160 Euros. Traditional cultivation activity is also observed near the populations. In the future, these threats could drive the taxon to VU or even EN in a short time. Notes: ���Unlike most other erect species of Begonia sect. Petermannia in Borneo, B. kapuashuluensis has a very short stem not exceeding 20 cm tall. Apart from its small size, B. kapuashuluensis is distinctive in having deep bluish green leaves which are light red to crimson beneath, often with a small cauline leaf at the first branch of the inflorescence., Published as part of Randi, Agusti, Ardi, Wisnu H., Girmansyah, Deden, Sitepu, Bina Swasta & Hughes, Mark, 2022, Three new species, one new record and an updated checklist of Begonia (Begoniaceae) from Kalimantan, Indonesia, pp. 62-72 in Phytotaxa 533 (1) on page 63, DOI: 10.11646/phytotaxa.533.1.3, http://zenodo.org/record/5973875, {"references":["Lin, C. W., Chung, S. W. & Peng, C. - I. (2014) Three new species of Begonia (sect. Petermannia, Begoniaceae) from Sarawak, Borneo. Phytotaxa 191: 129 - 140. https: // doi. org / 10.11646 / phytotaxa. 191.1.8","IUCN Standards and Petitions Subcommittee (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee."]}

Begonia belagaensis S.Julia, Sandakania 20: 133 (2015). Type: ��� MALAYSIA, Borneo, Sarawak, Belaga District, Sungai Chak (Tributary of Sungai Murum), 20 March 2014, Ling et al. BMHEP 3821 (holotype SAR). (Fig. 4). Distribution:��� Endemic to Borneo. In Sarawak recorded in Belaga District, and in Kalimantan this species is recorded from Samboja Forest Research (KHDTK Samboja), Tahura Bukit Soeharto, and Sepaku area, Penajam Paser Utara. All localities are near Balikpapan City. It is also recorded from one location in Sungai Lokang, Kapuas Hulu Regency, West Kalimantan. Specimens examined:��� INDONESIA, East Kalimantan, Kutai Kartanegara, Samboja, 0 o 59���00���S, 116 o 56���10���E, 45 m elev., 28 March 2020, Sitepu & Randi BSS 650 (WAN); East Kalimantan, Penajam Paser Utara, 9 November 2019, Sitepu, BSS 602 (WAN); East Kalimantan, PT. ITCI, Kenangan, Balikpapan, 50 m elev., 5 March 1991, Ambriansyah & Arifin AA94 (WAN). Notes:��� Although there are some differences between the specimens found in Kalimantan and the description in Julia et al. (2015), the specimens from Kalimantan have larger leaves (8���25 �� 4���15 cm) and inflorescences bearing up to 6 pistillate flowers, the protologue describes smaller (12���12.5 �� 11.5���12 cm) leaves, and inflorescences bearing 1���2 pistillate flowers). However comparison with images in Kiew et al. (2015) and correspondence with the collector of the type confirm that both are same species. Distinctive characters for the species shared between material from Sarawak and Kalimantan are large clumping habit, glabrous in all parts, leaf shape and texture, glandular bracts and bracteole margins, petioles deeply channeled above, and morphology and colour of male and female flowers. The records from Kalimantan are abundant at altitudes ranging from 30���220 m elev., and in Sarawak it is only recorded at 540���560 m elev., Published as part of Randi, Agusti, Ardi, Wisnu H., Girmansyah, Deden, Sitepu, Bina Swasta & Hughes, Mark, 2022, Three new species, one new record and an updated checklist of Begonia (Begoniaceae) from Kalimantan, Indonesia, pp. 62-72 in Phytotaxa 533 (1) on pages 69-70, DOI: 10.11646/phytotaxa.533.1.3, http://zenodo.org/record/5973875, {"references":["Julia, S., Kiew, R. & Yiing, L. C. (2015) A decade of Begonia (Begoniaceae) from Borneo. Sandakania 20: 129 - 154.","Kiew, R., Sang, J., Repin, R. & Ahmad, J. A. (2015) A Guide to Begonias of Borneo. Natural History Publications (Borneo), Kota Kinabalu. 293 pp."]}

Begonia patar Randi, sp. nov. B. sect. Petermannia (Fig. 2). Type: ��� INDONESIA, West Kalimantan Province, Sintang Regency, Kelam Permai District, Ensaid Panjang Village, Bukit Rentab, 0��8���7.72���N, 111��43'56.65"E, 55 m elev., 19 October 2020, A . Randi AR-1051 (holotype BO!; isotype WAN!). Diagnosis:��� It is allied to B. kiamfeei Kiew & S.Julia (2007: 215) in having a creeping habit and hairy leaves, but differs in having larger (8���16 �� 6���12 cm vs. 6.5���8.5 �� 5���8.5 cm) variegated (vs. uniform green) leaves, and pistillate flowers in pairs (vs. single) per node. A short creeping herb. Stem stout, unbranched, 5���26 cm long, 4���8 mm in diameter, zig-zag, covered with villous hairs, succulent, pink to crimson; nodes with conspicuous leaf and stipule scars, internodes 4���19 mm apart. Stipules persistent, asymmetric, broadly ovate to broadly elliptic, 5���10 �� 4���8 mm, with conspicuous hairs on main rib abaxially, glabrous adaxially, margin entire, apex acute to obtuse to retuse, erect then becoming recurved with aging, greenish-yellow when fresh, usually pinkish at base. Leaves simple, alternate, oblique; petiole to 12 cm long, 1.5���3 mm in diameter, with villous or pilose hairs, pink to brownish red; lamina ovate, 8���16 �� 6���12 cm (basal lobes included), strongly asymmetric with overlap basal lobes, margins dentate when young then becoming crenate by age and undulated, often with thin red margin, apex obtuse, acute to caudate; adaxial surface variegated, dark green to purplish-brown with cream to light green on venations, completely covered by pilose hairs coloured white or pink to brownish red, abaxial surface very striking with a combination of pink to red with cream to light green on venations, with sparse and scattered pilose hairs; venation palmate-pinnate, midrib distinguishable, with 2���4 lateral veins each side, other primary veins branching dichotomously; young leaves brownish-red, completely covered by dense hairs adaxially and looser with age. Inflorescence protogynous, terminal then becoming opposite of leaves with aging, erect, up to 27 cm long, 2���4 mm diameter at the base, with sparse pilose hairs, roughly zig-zag for whole length, cream-pink to dark red; pistillate flowers placed ⅓ ��� ⅔ of inflorescence length from the base, to 4 flowers, a pair for each node, rarely solitary, to 5 cm apart, peduncle to 4.5 cm long; upper distal to 12 cm long, peduncle 1.5���3 cm long, cyme branching to 2 orders, pinkish to red; bracteoles caducous, broadly ovate, 3���6 �� 3���5 mm, margin entire, apex acute to obtuse to retuse, white or sometimes slightly pinkish, symmetric. Staminate flower with 4 tepals, 2 outer and 2 inner, glabrous; pedicel slender, 5���8 mm long, 0.5���1 mm diameter, glabrous; outer tepals broadly ovate to orbicular, 5.5���8 �� 6���7 mm, margin entire, apex rounded, white; inner tepals smaller than outer ones, elliptic to oblanceolate, 3.9���4.2 �� 1.8���2.2 mm, margin entire, apex acute to rounded, white; androecium symmetric, 3���4 mm long, with 38���40 yellow stamens, filament 0.2���1 mm long, anthers obovate, 0.8���1.2 �� 0.5���0.8 mm, with divided apex, opened by slit. Pistillate flower at anthesis phase 13���20 mm across; pedicel ca. 10 mm long, ca. 1 mm diameter, white to pale pink, glabrous; ovary 3-locular, asymmetric or sometimes symmetric, 7���9 �� 12���14 mm (wings included), white, pale pink to pale purple; tepals 5, glabrous, 2 outer and 3 inner; outer tepals broadly ovate to orbicular, 6.5���7 �� 7 mm, margin entire, apex broadly acute to rounded, white or sometimes pinkish at base; inner tepals with 2 broader and 1 smaller, broader ones broadly elliptic to suborbicular, 6���7.5 �� 5���6.5 mm, apex broadly acute to rounded, white or sometimes pinkish at base, smaller one elliptic or obovate, ca. 5.5 �� 3 mm, apex acute to obtuse to rounded, white; styles 3, ca. 3 mm long, bifid, pale to golden yellow; stigmas anchor-shaped, forming a short papillose spiral band. Fruit nodding, 6���15 �� 8���18 mm (wings included), green to pink with dark red wings, glabrous; wings 3, subequal, often curved sideways, apex rounded, 3���6 mm wide at the widest point. Ecology:��� Creeping on vertical granite rocks at 50���100 m elev. This species grows directly on the surface of granite rocks or on the surface of thin mosses with medium light intensity. Distribution:��� Endemic to Borneo, so far it has only been found in Bukit Rentab, Ensaid Panjang Village, Sintang Regency, West Kalimantan. Etymology: ���The epithet of this species is derived from the local name patar, which means patterned from the Dayak Desa language, referring to the colour variation of the leaves. Provisional Conservation Status:��� Critically endangered (CR) B1ab(iii) + B2ab(iii) (IUCN, 2019). This species is found on a single small hill and is limited to rocky cliffs at the foot of the hill on the south side. Three subpopulations were found in the area with an EOO of 0.01 km �� and AOO of 4 km �� only. The habitat of the population is very easy to reach, and the distribution area is also a tourist location that is free to be entered by anyone. Although the habitat is a protected forest, forest fires have occurred several times in this location and shifting cultivation activities of local communities are still very active in the area. The population could also be threatened due to collection by plant hunters for use as ornamental plants. These threats can push this species towards possible extinction in a short time if there is no conservation effort. Therefore, ex-situ conservation of this species is urgently needed. Uses:��� The Dayak Desa people who live in the longhouse of Ensaid Panjang Sintang use it as a mixture of traditional ingredients to protect women after childbirth and their babies from demonic disturbances, besides that it is also used as a traditional herb to treat headaches. Notes:��� Begonia patar has a stout stem, 5���26 cm long and short internodes 0.4���1.9 cm apart, in contrast to B. kiamfeei which has a much more slender stem up to 50 cm long and internodes 2.5���4.5 cm long. The leaves of B. patar are distinctly variegated with a combination of dark green to purplish-brown with cream to light green on the venation adaxially and pink to red with cream to light green on the venation abaxially, while B. kiamfeei leaves are mid-green with pale green veins adaxially and paler beneath. The pistillate flowers of B. patar are in groups of up to 4 flowers, in a pair for each node, inner tepals 3 with 2 large and one smaller tepal in between, while B. kiamfeei bears up to 6 flowers which are solitary at each node, inner tepals 3 of the same size and shape. The habitat of the two species is also different, as B. patar grows on granite rocks, while B. kiamfeei grows on limestone. The habit, and attractive variegated ovate leaves of B. patar are also superficially similar to B. conipila Irmsch. ex Kiew (2001a: 287), however it has pale veins on a dark background, whereas B. conipila has dark veins on a pale background. In addition, some key characters are distinctive like the stipules broadly ovate to broadly elliptic in B. patar, while lanceolate in B. conipila. The petiole of B. patar is much longer (up to 12 cm long vs. to 5 cm) compared with B. conipila. Inflorescence in B. patar is terminal then becoming opposite to the leaves with ageing, up to 27 cm long, with two pairs of pistillate flowers at ⅓ ��� ⅔ of inflorescence length from the base, whereas B. conipila has axillary inflorescences, up to 9.5 cm long, with a single basal pistillate flower. The number of stamens is 38���40 in B. patar, and 10���11 in B. conipila. Their habitats are also very different, as B. patar grows on vertical granite rocks to 100 m elev., and B. conipila grows on limestone to ca. 1170 m elev., Published as part of Randi, Agusti, Ardi, Wisnu H., Girmansyah, Deden, Sitepu, Bina Swasta & Hughes, Mark, 2022, Three new species, one new record and an updated checklist of Begonia (Begoniaceae) from Kalimantan, Indonesia, pp. 62-72 in Phytotaxa 533 (1) on pages 65-67, DOI: 10.11646/phytotaxa.533.1.3, http://zenodo.org/record/5973875, {"references":["IUCN Standards and Petitions Subcommittee (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee.","Kiew, R. (2001 a) Begonia conipila Irmsch. ex Kiew (Begoniaceae) from the Gunung Mulu National Park, Sarawak, Malaysia. Gardens' Bulletin Singapore 53: 287 - 289."]}

Begonia kapuashuluensis Randi & Ardi, sp. nov., B. sect. Petermannia (Fig. 1). Type: — INDONESIA, West Kalimantan Province, Kapuas Hulu Regency, Boyan Tanjung District, 0°20'44.84"N, 112°25'4.53"E, 110 m elev., 10 July 2017, A . Randi AR-1022 (holotype BO!). Diagnosis:— It is allied to B. darthvaderiana C.W.Lin & C.I Peng (Lin et al. 2014: 132) in habit and floral characters, but differs in being a smaller plant up to 20 cm (vs. 25–70 cm) height with smaller leaves 9–14 × 4–7 cm (vs. 13–22 × 8–13 cm), deep bluish green (vs. blackish green with a narrow pale margin) leaves, and more stamens (22–31 vs. 7–11). A small herb, erect, up to 20 cm tall. Stem with 1–3 branches, 4–7 mm in diameter at the base, glabrous, bright red to brownish, fleshy and succulent, internodes 1–3 cm apart. Stipules caducous, asymmetric, translucent, glabrous, elliptic to lanceolate, 10–15 × 3–5 mm, with a stiff main rib and many parallel red veins; margin entire, apex acute with a short-pointed tip; pale green to red to brownish. Leaves 4–7, simple, alternate, oblique, glabrous; petiole 1–4 cm long, red to brownish, glabrous; lamina ovate, 9–14 × 4–7 cm (basal lobes included); strongly asymmetric with a well-developed basal lobe on one side giving a cordate appearance, base unequal, basal lobes 1–3 cm long, margins minutely denticulate, generally with a narrow dark red border adaxially that is clearly visible on young leaves, apex acuminate; adaxially shiny, deep bluish-green, surface flat or slightly bullate, abaxially light red to crimson, glabrous; venation palmate-pinnate, midrib distinguishable, with 3–4 lateral veins each side, other primary veins branching dichotomously; young leaf brownish abaxially. Inflorescence protogynous, terminally or axillary, erect, 6–12 cm long; basal branch with a pair (rarely 2 pairs) of pistillate flowers on short peduncle ca. 1 cm long, often with leaves at the first branch; upper distal to 10 cm long, zig-zag, branching cymosely, peduncle to 5 cm long, cymes branching to 3 orders, crimson to brownish, glabrous; bracts caducous, translucent, glabrous; bract on nodes of pistillate flower elliptic to lanceolate ca. 5 × 1 mm, cream to pinkish, margin entire, apex acute to cuspidate; bracts on higher part of inflorescence similar but smaller. Staminate flower with 2 pink tepals, each tepal ovate to orbicular or obovate, 3–5 × 3–5 mm, glabrous, margin entire, apex acute to rounded; pedicel pink to crimson, 2–5 mm long, glabrous; androecium symmetric with 22–31 yellow stamens, filament 0.6–1.2 mm long, anthers obovate 0.7–1.4 mm long, apex opened by slit. Pistillate flower 10–20 mm across, each flower blooming alternately; pedicel pink to brownish red, 4–8 mm long, ca. 1 mm in diameter, glabrous; ovary 3-locular, asymmetric, 7–11 × 10–15 mm (wings included), yellowish-green in the middle, red to brownish on the wings; tepals 5, glabrous, 2 outer and 3 inner, all pink and elliptic, 6–8 × 4–5 mm, apex acute to obtuse; styles 3, bifid, 2–4 mm long, golden yellow; stigmas narrowly Y-shaped, forming a papillose spiral band. Fruits nodding, 7–15 × 10–18 mm (wings included), pink to crimson, glabrous; wings 3, subequal, nearly parallel but with rounded, apex acute or mucronate, 3–4 mm wide at the widest point. Distribution: —Endemic to Borneo, widespread in the western part of the Muller Mountains that administratively belong to Kapuas Hulu Regency of West Kalimantan Province, Indonesia. Habitat: —Humid areas near rivers or narrow valleys under a dense canopy of mixed dipterocarp forest at 100– 300 m elev. Etymology: —The epithet refers to the name of regency where this species was found, Kapuas Hulu. Provisional Conservation Status: —Near threatened (NT) (IUCN, 2019). This species is observed in seven localities and locally abundant in the western part of Muller Mountains. Although based on EOO = 184.6 km ² and AOO = 28 km ² this species potentially qualifies for the endangered category, but we have observed that this species is growing in relatively undisturbed forest and in several protected forest areas. However, the populations could be threatened due to extraction by plant hunters to be sold as an ornamental, as this beautiful species is well known among Begonia enthusiasts. It has the popular trade name Begonia “temuyuk” and is for sale on commercial and social media sites for prices ranging from 50 US dollars to 160 Euros. Traditional cultivation activity is also observed near the populations. In the future, these threats could drive the taxon to VU or even EN in a short time. Notes: —Unlike most other erect species of Begonia sect. Petermannia in Borneo, B. kapuashuluensis has a very short stem not exceeding 20 cm tall. Apart from its small size, B. kapuashuluensis is distinctive in having deep bluish green leaves which are light red to crimson beneath, often with a small cauline leaf at the first branch of the inflorescence.

Begonia sangkulirangensis Ardi, Girm. & Randi, sp. nov. B. sect. Petermannia (Fig. 3). Type:��� INDONESIA, East Kalimantan Province, Karst Sangkulirang, Bengalon, Goa Tewet Trail, 1��3���47.9���N, 117��16���11.4���E, ca. 80 m elev. (cultivated at Bogor Botanic Garden from material collected in the wild (Hughes M., Girmansyah D., Yeats H. & Ardiyani M. EKBOE138), 4 December 2019, Wisnu H. Ardi WI 684 (holotype BO!). Diagnosis:��� The erect habit and peltate leaves of B. sangkulirangensis are similar to B. nothobaramensis Joffre (2015: 35) from Brunei but it can be easily distinguished by its shorter (50���60 cm vs. 100 cm) habit, smaller (7���12 �� 3.5���5.5 cm vs. 9.5���18 �� 5���9 cm) lamina, more (45���55 vs. ca. 36) stamens, female inflorescence consistently with a single (vs. two) flower on a shorter (10���13 mm vs. 17���20 mm) pedicel, ovary wing shape cuneate (vs. rounded) at the base and apex. Begonia sangkulirangensis also differs from both B. baramensis and B. nothobaramensis in having a thicker and more succulent leaf lamina. An erect herb, up to ca. 50 cm tall. Stem branched, nearly glabrous except for moderate microscopic glandular hairs, reddish-brown, internodes 2���9 cm apart. Stipules caducous, glabrous, elliptic, 6���8 �� 2���4 mm, midrib prominent, margin entire, translucent, apex narrowed into bristle up to 1.5 mm long; whitish-greenish. Leaves simple, alternate, glabrous; petioles 2���5 cm long, concolourous with the stem, terete; lamina peltate, coriaceous, elliptic, 7���12 �� 3.5���5.5 cm, asymmetric, apex acuminate, margin subentire, serrate from the middle part upward to the apex, adaxial surface dark green with brownish veins, abaxial surface pale green, veins reddish to brownish; venation palmate-pinnate, primary veins 5���6, actinodromous, secondary veins craspedodromous.Inflorescence protogynous; female inflorescence solitary, one node basal to male inflorescence or further separated, peduncle 3���5 mm long, reddish-green, glabrous, bracteoles minute, hairlike, persistent; upper distal that bearing male inflorescence paniculate, composed of up to 4 simple monochasium with 4���7 flowers, peduncle 5���8 mm long, glabrous; bracts stipule-like, persistent, ovate, ca. 4 �� 1.5 mm, translucent, midrib slightly prominent, pale green, glabrous, apex acuminate and narrowed into bristle ca. 1 mm long; bracteoles persistent, minute. Staminate flower pedicel up to 7.5 mm long, whitish-green, glabrous; tepals 2, broadly ovate, 4���6 �� 5���7 mm, greenish-red or dull cream, glabrous, margin entire, apex rounded; androecium symmetric with 48���55 yellow stamens, filaments up to ca. 1 mm long, fused at the base, anthers ca. 0.5 mm long, dehiscing through unilaterally positioned slits ca. �� as long as the anthers. Pistillate flowers: pedicels 10���13 mm long, pale green, glabrous; ovary 3-locular, cylindrical, 16���18 �� 2���3 mm (wings excluded), pale green, glabrous, placentae bilamellate, wings 3, subequal, base cuneate to rounded, apex subcuneate, widest point up to 7 mm (1 / 3 from the apex); tepals 5, glabrous, white tinged with pink and green, unequal, one smaller elliptic, 5���6 �� 2���3 mm, the four larger ovate, 8���9 �� 4.5���6 mm, margin entire, apex rounded; style ca. 4.5 mm long, basally fused, 3-branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, orange. Fruit peduncle up to 5 mm long; pedicels up to 15 mm long, pendulous and recurved; seed-bearing part cylindrical, 16���19 �� 3���4 mm (wings excluded), wing shape as for ovary, widest point up to ca. 8 mm. Seeds barrel-shaped, 0.2���0.3 mm long. Distribution: ���Endemic to Borneo, so far only known from the type locality in the Sangkulirang-Mangkalihat Limestone Karst Ecosystem, East Kalimantan Province, Indonesia. Habitat:��� This species was found on a limestone cliff in a shallow cave in deep shade beneath scrubby karst vegetation. It was growing in thin dusty soil on a slightly damp mossy rock. Etymology:��� The epithet refers to the name of Sangkulirang, the Limestone Karst Mountain Ecosystem where this species was found. Provisional Conservation Status:��� Vulnerable (VU, D2). This species is only known from single collection from the Sangkulirang Mangkalihat Limestone Karst Ecosystem. The area does not yet have legal protected status, and there are clear signs of anthropogenic disturbance (oil palm plantations and mining) around the karst formations. As a karst micro-endemic it therefore is ���prone to the effects of human activities or stochastic events within a very short time period in an uncertain future��� (IUCN Standards and Petitions Subcommittee 2019). An ex-situ initiative has been started with plants being cultivated at Kebun Raya Bogor (Bogor Botanic Garden). Notes: ���There are four other caulescent species in B. sect. Petermannia in Borneo with conspicuously peltate leaves: B. amphioxus Sands (1990: 81), B. baramensis Merrill (1928: 529) B. layang-layang Kiew (2001b: 272) and B. nothobaramensis Joffre (2015: 35). Begonia sangkulirangensis is closest to B. nothobaramensis as discussed in the diagnosis above, and B. baramensis is a much larger plant, reaching up to 3 m tall (Kiew et al. 2015). Begonia amphioxus and B. layang-layang do not appear to be closely allied, both differing most obviously in their leaves which are acute at the base and tip., Published as part of Randi, Agusti, Ardi, Wisnu H., Girmansyah, Deden, Sitepu, Bina Swasta & Hughes, Mark, 2022, Three new species, one new record and an updated checklist of Begonia (Begoniaceae) from Kalimantan, Indonesia, pp. 62-72 in Phytotaxa 533 (1) on pages 67-69, DOI: 10.11646/phytotaxa.533.1.3, http://zenodo.org/record/5973875, {"references":["Joffre, A. A., Kiew, R., Julia, S. & Repin, R. (2015) The Begoniaceae of Brunei Darussalam, Borneo, including two new species. Sandakania 20: 7 - 50.","IUCN Standards and Petitions Subcommittee (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee.","Sands, M. J. S. (1990) Six new Begonias from Sabah. Kew Magazine 7: 57 - 85.","Merrill, E. D. (1928) A collection of plants from Sarawak. Sarawak Museum Journal 3: 513 - 557.","Kiew, R. (2001 b) The limestone Begonias of Sabah, Borneo - flagship species for conservation. Gardens' Bulletin Singapore 53: 241 - 268.","Kiew, R., Sang, J., Repin, R. & Ahmad, J. A. (2015) A Guide to Begonias of Borneo. Natural History Publications (Borneo), Kota Kinabalu. 293 pp."]}