1. Begonia aptera Blume [§ Platycentrum], Enum. Pl. Javae 1: 97 (1827). Diploclinium apterum (Blume) Miq., Fl. Ned. Ind. 1: 691 (1856).

– Type: Indonesia, Sulawesi, Tondano, s.coll., s.n. (lectotype L [Herb. Ludg. Bat. 898194-39], designated by Hughes [2008]) .

Begonia cristata Warb. ex L.B.Sm. & Wassh., Phytologia 52: 442, pl. 2 (1983). – Type: Indonesia, Sulawesi, North Sulawesi, Minahasa, Tomohon, iv 1984, K.F. & P.B. Sarasin 288 (lectotype K [K000761122], designated by Smith & Wasshausen [1983]).

Begonia renifolia Imsch., Bot. Jahrb. Syst. 50: 379 (1913). – Type: Indonesia, Sulawesi, North Sulawesi, Minahasa, Bojong, N. Wallich 15188 (holotype B [B100238021]).

Begonia aptera subsp. hirtissima Girm. & D.C.Thomas, Reinwardtia 13(1): 72 (2009). – Type: Indonesia, Sulawesi, Southeast Sulawesi, Kolaka Regency, Ranteangin District, Tinukari Village, Mt Mekongga, 21 iii 2006, D. Girmansyah DEDEN654 (holotype BO; isotypes E [E00678415, E00678417], K, L, US).

Additional literature. Hughes (2008) [synonymy]; Tebbitt (2003) [as Begonia cristata, but emphasising likely conspecificity with B. aptera; drawing, distribution map]; Ardi et al. (2018) [synonymy, photographic plate, distribution map]; Hughes et al. (2018); Thomas & Ardi (2020) [photographic plate].

Distribution. Indonesia: Sulawesi (all provinces), Moluccas and western New Guinea (Yapen Island) (Figure 2).

Habitat. Primary to severely disturbed lowland to montane forests at 140–2000 m elevation.

Proposed IUCN conservation category. Least Concern (LC) (Ardi et al., 2018).

Additional specimens examined. INDONESIA. Sulawesi. Northern arm of Sulawesi. Western North Sulawesi: Bukit Dako, Lakatan Distr., Toli-toli, 25 ii 1985, Ramlanto & Z. Fanani 527 (BO, L) ; Mt Sojol, 25 ii 2000, G.C.G. Argent et al. 151 (E); Gunung Sidole, 26 xii 2018, E. Damayanti et al. ED11 (CEB); Sojol foothill, Balungkang village, 7 viii 2018, W.H. Ardi WI305 (BO, KRB, SING). Central North Sulawesi. Gorontalo: Olama River, 9 iii 2002, M. Mendum et al. 49 (A, E, L) ; Gunung Boliohutu, 23 iii 2002, M. Mendum et al. 186 (E). Eastern North Sulawesi. Manado: Tonsealama, 13 xii 1932, C.A. Wisse 78 (BO); Mt Klabat: 27 vi 1956, L.L. Forman 248 (K, L, P) ; 30 i 2019, W.H. Ardi WI387 (BO, KRB, SING); Kali Waterfall, 31 i 2019, W.H. Ardi WI392 (BO, KRB, SING). Minahassa: Bojong, 1888, O. Warburg 15187 (B [2]); Gunung Lokon, 4 vii 1956, L.L. Forman 371 (K, L) ; Mt Soputan: 11 x 1973, E.F. de Vogel 2503 (L) ; S.H. Koorders 16244B (L); S.H. Koorders 16245B (B, L); S.H. Koorders 16246B (B); Mt Manimporok, East of Mt Soputan, 8 ii 2009, D. Girmansyah DEDEN1103 (BO) ; G. Potong, 28 ii 2001, P.J.A. Kessler 2951 (L) . Tomohon: 6 vi 1954, A.H.G. Alston 15679 (A, BM, L). G. Masarang: 22 vi 1956, L.L. Forman 207 (K); 20 ii 2008, M. Ardiyani et al. 104 (BO, E); 17 iii 2006, S. Sunarti SSS06 -010 (BO); 17 iii 2006, S. Sunarti SSS06 -022 (BO); 2 ii 2019, W.H. Ardi WI397 (BO, KRB, SING). Lokon: S.H. Koorders 12648B(BO) ; Kayawu Village, 17 ii 2009, D. Girmansyah DEDEN1269 (BO). G. Mahawu: Rurukan Village, 15 ii 2009, D. Girmansyah DEDEN1233 (BO); xii 2003, Ambriansyah AA 2641 (WAN); Nr Pangi, 7 iii 1990, J.S. Burley et al. 3717 (K, L). Bolaang-Mongondow: Goeroepahi, 27 iii 1917, Kauderns 61 (L). Dumoga Bone National Park: Gunung Mogogonipa: 6 iv 1985, E.F. de Vogel & J.J. Vermeulen 7020 (L); 6 i 1996, M. Kato et al. 382 (A); Bogani Nani Wartabone National Park, Mauk Malotong, 21 v 2002, T. Uji 4537 (BO) ; Paya-paya, Gunung Ambang Nature Reserve, 2 xi 2016, Barber et al. BAAK35 (BO, E) .

Central Sulawesi Province: Todjamboe, 23 vi 1929, G.K. Kjellberg 1750 (B) ; Menado, Kampong Sidaoenta, 13 vii 1939, S. Bloembergen 4224 (BO) ; Palu-Parigi, 17 iv 1975, W. Meijer 9329 (BO, L) ; E of Tongoa, 24 ii 1981, H. Johansson et al. 58 (L) ; Tongoa, 25 ii 1981, Johansson 76 (K, L) ; Palolo, Kamarora, 15 iii 2001, P.J.A. Kessler 3025 (L) ; Takolekayu, 14 i 2008, M. Ardiyani et al. 152 (BO, E) ; Uwe lutu, C. Pangi Binangga, 20 vii 2018, W.H. Ardi WI214 (BO, KRB, SING) ; Saluopa waterfall, 31 vii 2018, W.H. Ardi WI254 (BO, KRB, SING) ; Pendolo, 2 viii 2018, W.H. Ardi WI283 (BO, KRB, SING) ; Gunung Mad, Pegunungan Biru, Poso-Napu Road Divided, 3 viii 2018, W.H. Ardi WI293 (BO, KRB, SING) ; Lonsi Waterfall, Taloyon, Pagimana, 14 ii 2019, W.H. Ardi WI426 (BO, KRB, SING). Lore Lindu National Park: Menado, G. Ngilalaki, 11 vii 1939, S. Bloembergen 4125 (L) ; Ponoh, 3 km NE of Toro Village, 6 xii 2007, D. Cicuzza 464 (E) ; Tambing Lake vicinity, 4 viii 2018, W.H. Ardi WI303 (BO, KRB, SING). Mt Nokilalaki: 6 iii 2008, D. Cicuzza 794 (E); M. shelter 1, 24 vii 2018, W.H. Ardi WI217 (BO, KRB, SING); track to shelter 2, 24 vii 2018, W.H. Ardi WI218 (BO, KRB, SING). Luwuk: Laumarang Waterfall, 9 ii 2019, W.H. Ardi WI414 (BO, KRB, SING) ; Batu Tikar Waterfall, 9 ii 2019, W.H. Ardi WI417 (BO, KRB, SING) ; Mt Loloa–Mt Beabis, 27 ix 1938, P.J. Eyma 3839 (BO, L) ; Hanga-hanga waterfall, 8 iv 2008, D.C. Thomas & W.H. Ardi DCT08-22 (BO, E). Bunta: Sumber Agung, Gunung Hek, 25 ii 2004, Hendrian et al. 884 (E) ; G. Hek, 9 iv 2008, D.C. Thomas & W.H. Ardi DCT08 -27 (BO, E) ; Sumber Agung village, Mt Hek, 10 iv 2008, D.C. Thomas & W.H. Ardi DCT08-31 (BO, E) ; Mt Hek, 10 iv 2008, D.C. Thomas & W.H. Ardi DCT08-36 (BO, E). M. Katopas . Wotusongu Village: 6 v 2008, D.C. Thomas & W.H. Ardi DCT08-66 (BO, E) ; 11 v 2008, D.C. Thomas & W.H. Ardi DCT08-73 (BO, E). Mt Lumut: 10 iv 2008, D.C. Thomas & W.H. Ardi DCT08-54 (BO, E) ; 21 iv 2008, D.C. Thomas & W.H. Ardi DCT08 -55 (BO, E); 21 iv 2008, D.C. Thomas & W.H. Ardi DCT08 -57 (BO, E); 23 iv 2008, D.C. Thomas & W.H. Ardi DCT08-59 (BO, E). Banggai Islands: KM 13, Potongan Panjang, Tinakung Selatan, 18 ix 2014, D. Girmansyah DEDEN2039 (BO) ; Nandik, Tinakung Utara, 23 ix 2014, D. Girmansyah DEDEN2081 (BO) ; Road to Lumbi-lumbia waterfall, South Bulagi, 20 ix 2014, D. Girmansyah DEDEN2602 (BO). Sopu Valley: 24 iii 1979, E. Hennipman 5588 (A, BO, K, L) ; 2 v 1979, E.F de Vogel 5174 (L); 26 v 1979, E. Hennipman 5633 (BO, K, L). Road to Kulawi: 29 vii 2018, W.H. Ardi WI239 (BO, KRB, SING) ; 29 vii 2018, W.H. Ardi WI246 (BO, KRB, SING). Tentena-Bada Road: 1 viii 2018, W.H. Ardi WI267 (BO, KRB, SING) ; 1 viii 2018, W.H. Ardi WI273 (BO, KRB, SING). West Sulawesi Province: Stream about 60 km from Mamasa to Polewali road, 3 viii 1998, W.S. Hoover & H. Wiriadinata 889 (BO). Mamasa: Mamasa-Tabang, Polewali, 21 vi 1974, Shuji Yoshida 1236 (BO); Tabang, Tanduk Kalua Village, 21 xi 2019, W.H. Ardi et al. WI505 (BO, CEB, SING) ; Pesapa Kurrak Village, 23 xi 2019, W.H. Ardi et al. WI543 (BO, CEB, SING) ; Seppang Village, 24 xi 2019, W. H. Ardi et al. WI561 (BO) ; Tawalian Timur, 26 xi 2019, W.H. Ardi WI594 (BO, CEB, SING) ; Sumarorong, Sarambu Liawan, 27 xi 2019, W.H. Ardi et al. WI608 (BO, CEB, SING). G. Gandang Dewata . Tetean Waterfall: 21 iv 2016, Kartonegoro et al. ARK929 ; 21 iv 2016, Kartonegoro et al. ARK939 (BO). G. Mambulinin: 11 v 2009, D.C. Thomas & W.H. Ardi DCT09 -126 (BO, E) ; Sulawesi Barat, 13 v 2009, D.C.Thomas & W.H. Ardi DCT09-130 (BO, E). South Sulawesi Province: Pasoei, 9 vi 1929, G.K. Kjellberg 1627 (B) ; Maboesa-Sae, 21 iii 1937, P.J. Eyma 1188 (BO) ; Masamba, 4 viii 1937, P.J. Eyma 1550 (BO); Masamba, 4 viii 1937, P.J. Eyma 1551 (BO) ; Faruhumpenai, Toromu village, Luwu Regency, 16 ii 1986, Wardi 004 (BO) ; Pantawanan, Eran Batu, Baraka district, 29 viii 1994, D. Girmansyah DEDEN014 (BO) ; Mt Pasaparan, Mts Latimojong, 27 x 1994, Tahan Uji & M. Amir 2506 (BO) ; stream about 25 km from Palopo to Rantepao Road, 3 xii 1998, W.S. Hoover & H. Wiriadinata 892 (BO); Road between Wotu and Lake Poso, 20 ii 2000, G. Argent et al. 116 (E) ; Buntu Area, Kpg Lokkok, 15 ix 2003, J.J. Vermeulen 2300 (L). Rantemario: 5 iii 2000, G.C.G. Argent et al. 238 (E) ; 7 xi 1993, S. Kofman 210 (L); 27 iv 2009, D.C. Thomas & W.H. Ardi DCT09 -95 (BO, E); 27 iv 2009, D.C. Thomas & W.H. Ardi DCT09-99 (BO, E). Mangkutana-Pendolo: 3 ii 2004, J.J. Vermeulen 2524 (L) ; 3 v 2009, D.C. Thomas & W.H. Ardi DCT09 -109 (BO, E); 3 v 2009, D.C. Thomas & W.H. Ardi DCT09 -118 (BO, E); 3 v 2009, D.C. Thomas & W.H. Ardi DCT09-119 (BO, E). Tana Toraja. Rantepoa-palopo: 2 ii 2004, J.J. Vermeulen 2409 (L) ; 30 iv 2009, D.C. Thomas & W.H. Ardi DCT09-103 (BO, E). Southeast Sulawesi Province: Kendari- Kolaka, 23 v 2008, A.R. Kartonegoro ARK253 (BO) ; Mt Lasumowo, Mowewe District, 24 v 2008, D. Girmansyah DEDEN1037 (BO, K) ; Wawatobi-Lasolo road divide, 12 ii 2017, W.H. Ardi WI151 (BO, KRB, SING). North Kolaka: 17 iii 2006, H. Wiriadinata et al. 12976 (BO) ; along logging road between km 14 and km 17, 17 iii 2006, H. Wiriadinata et al., DEDEN573 (BO) ; along logging road between km 17 and pos 4, 18 iii 2006, H. Wiriadinata et al., DEDEN575 (BO). Rante Angin: Tinukari Village, 20 xii 2009, E.A. Widjaja & A. Suyadi EAW919 (BO) ; 7 viii 2009, A. Hidayat et al. 4186 (BO); 10 viii 2009, A. Hidayat et al. 4285 (BO); 3 viii 2009, D. Potter et al. 090803-15 (BO); 29 vi 2010, E.A. Widjaja & A. Suyadi EAW9058 (BO); 30 vi 2011, E.A. Widjaja et al. EAW9721 (BO). M. Watuwila: 25 iii 1929, G.K. Kjellberg 1032 (BO) ; Mt Pondunaa, 12 v 2008, A.R. Kartonegoro ARK 231 (BO) ; Mt Sophura, 12 v 2008, D. Girmansyah DEDEN859 (BO, K) ; Mt Pondunaah, 13 v 2008, D. Girmansyah DEDEN880 (BO, K). Kolaka: Kec. Uluiwoi, Ds. Ahiluhu, Marmer Cave, 17 iii 2006, H. Wiriadinata et al., DEDEN746 (BO) ; Bite forest, Lalingato, Tirawuta Subdistrict: 17 vii 2008 ; A. Hidayat AH 3677 (BO, K); 17 vii 2008, A. Hidayat AH 3678 (BO, K). Province unknown: iv 1894, K.F. & P.B. Sarasin 488 (B [2]) ; 16 vi 1894, K.F. & P.B. Sarasin 488 (B [2]); unknown 1721 (L); Forst s.n (BO); Todjambor, 21 iii 1929, G. Kjellberg 1701 (BO) .