Eleven new records, three new species and an updated checklist of Begonia from Kalimantan, Indonesia

Abstract

The Begonia flora of Kalimantan is very poorly known, in marked contrast to that of Brunei, Sabah and Sarawak. Here we publish eleven new records and three new species (B. bawangensis Girm., Randi & M.Hughes, B. pendulina Girm. & M.Hughes and B. recurvata Girm. & M.Hughes, all in Begonia sect. Petermannia) (Klotzsch) A.DC. for Kalimantan. Provisional conservation assessments according to IUCN criteria are provided for the new species.

Keywords. Begonia bawangensis, Begonia pendulina, Begonia recurvata, Borneo, endemism, limestone karst, taxonomy

Full text

33
Gardens' Bulletin Singapore 72(1): 33–58. 2020
doi: 10.26492/gbs72(1).2020-05
Eleven new records, three new species and an updated
checklist of Begonia from Kalimantan, Indonesia
M. Hughes1, D. Girmansyah2, A. Randi3 & H.N.R. Ningsih4
1Royal Botanic Garden Edinburgh, 20A Inverleith Row,
Edinburgh EH3 5LR, Scotland, U.K.
m.hughes@rbge.ac.uk
2Botany Division, Research Center for Biology,
Indonesian Institute of Sciences, Jl. Raya Jakarta Bogor Km. 46,
Cibinong 16911, Bogor, Indonesia
3Faculty of Forestry, Bogor Agricultural University,
Kampus IPB Darmaga PO Box 168, 16001 Bogor, Indonesia
4Arboretum Sylva UNTAN, Universitas Tanjungpura, Pontianak,
Kalimantan Barat, Indonesia
ABSTRACT. The Begonia ora of Kalimantan is very poorly known, in marked contrast to
that of Brunei, Sabah and Sarawak. Here we publish eleven new records and three new species
(B. bawangensis Girm., Randi & M.Hughes, B. pendulina Girm. & M.Hughes and B. recurvata
Girm. & M.Hughes, all in Begonia sect. Petermannia) (Klotzsch) A.DC. for Kalimantan.
Provisional conservation assessments according to IUCN criteria are provided for the new
species.
Keywords. Begonia bawangensis, Begonia pendulina, Begonia recurvata, Borneo, endemism,
limestone karst, taxonomy
Introduction
A total of eleven Begonia species have been conrmed as occurring in Kalimantan
to date, based on specimen records in Hughes (2008) and Hughes et al. (2015,
continuously updated), the recent publication of six species by Girmansyah & Susanti
(2015), Girmansyah (2017) and Ardi et al. (2019), and a new record by Kiew et al.
(2018). This contrasts with 241 species in the area comprising Sarawak, Sabah and
Brunei, after intensive taxonomic work by Ruth Kiew, Julia Sang, Rimi Repin and
collaborators (e.g. Kiew et al., 2015; Sang et al., 2015a); this gives an average of 1.2
species per 1000 km2 for a combined area of 204,000 km2. For Kalimantan, with an area
of 743,000 km2, the average number of species per 1000 km2 is 0.01, a difference of
100-fold. These gures also reect the number of collections of Begonia specimens in
Borneo, which is 206 specimens in Kalimantan compared to 1705 in Sabah-Sarawak-
Brunei combined (Hughes et al., 2015, continuously updated). A recent estimate of
the total expected species number for Begonia on Borneo is 600, making it the largest
genus of plants on the island (Sang & Kiew, 2014). Hence there is obviously a massive
taxonomic decit in the Begonia of Kalimantan, which here we take the rst small
steps to rectify.

Gard. Bull. Singapore 72(1) 2020
34
The species currently known from Kalimantan are either fairly widespread taxa initially
described from outside Kalimantan (Begonia baramensis Merr., B. fuscisetosa Sands
and B. gueritziana Gibbs) or narrowly endemic taxa described from deep within the
region (B. dolichobracteata Girm., B. duhungensis Girm., B. inggitiae Ardi & Girm.,
B. ltahensis Girm., B. mentewangensis Girm. and B. walteriana Irmsch.), or near the
border (B. dracopelta Ardi and B. promethea Ridl.). Following expeditions to East
Kalimantan in 2016 (the Sangkulirang Mangalihat karst) and to West Kalimantan in
2017 (Gunung Niut and Gunung Bawang) and 2019 (Bengkayang Regency), and further
examination of herbarium specimens in BO, E and WAN herbaria, here we publish
eleven new records and three new species for Kalimantan, with eld photographs
where available. These bring the checklist for Kalimantan to 25 species (Appendix
1; excluding records from smaller islands politically belonging to Kalimantan, but
not part of Borneo). All cited specimens are available as images from Hughes et al.
(2015, continuously updated) and many from the website of the Royal Botanic Garden
Edinburgh.
New records
Begonia bayae S.Julia, Phytotaxa 252(1): 22 (2016). – TYPE: Malaysia, Sarawak,
Lubok Antu District, Batang Ai National Park, Lubang Baya, Bebiyong Mit trail,
adjacent to the Ranger Post, 1°18′00″N 112°04′10″E, 200 m, 2 August 2015, Julia et
al. SFC 2762 (holotype SAR; isotypes KEP, SNP). (Fig. 1)
Distribution. Batang Ai National Park in Sarawak and Betung Kerihun National Park
in West Kalimantan (Fig. 2).
Specimens examined. INDONESIA: West Kalimantan: Sungai Tamabaloh, anak Sungai
Tekelan, DAS Embaloh, Betung Kerihun National Park, 23 Dec 2011, Ardiyani et al. s.n.
(photographic voucher); Putussibau, Nanga Pari, Betung Kerihun National Park, 1 Mar 1999,
Sidiyasa 1948 (E [E00313073]); Sungei Obat, 29 Jan 1925, Winkler 1352 (E [E00885864]);
Sungei Obat, 31 Jan 1925, Winkler 1390 (E [E00885863]).
Notes. The lime green leaves and dark brown veins are distinctive. The specimens
Sidiyasa 1948, Winkler 1352 & 1390, which represent the southernmost localities,
have more elongate leaves than the type, but are a good match in terms of venation
and fruit shape.
Begonia calcarea Ridl., J. Straits Branch Roy. Asiat. Soc. 46: 260 (1906); Kiew &
Geri, Gard. Bull. Singapore 55: 115 (2003); Kiew et al., Guide to Begonias of Borneo
68 (2015); Kiew et al., Gard. Bull. Singapore 68: 241 (2016); Yiing et al., Phytotaxa
381(1): 13 (2018). – TYPE: Malaysia, Sarawak, Gunung Bra’ang, Haviland s.n. (type
not located). (Fig. 3)

35
New species and records of Begonia from Kalimantan
Distribution. Widespread in Sarawak in the Bau, Bintulu, Kapit, Kuching and Tatau
districts, and in Kalimantan in the Bengkayang Regency; found on limestone and
sandstone (Fig. 2).
Specimens examined. INDONESIA: West Kalimantan: Bengkayang Regency, Tikalong
District, Tunang Village, Tikalong Waterfall , 2 Dec 2017, Girmansyah et al. WEKBOE3 (BO,
E [E00959307]); Bengkayang Regency, Umbo, base of Gunung Niut, 7 Dec 2017, Girmansyah
et al. WEKBOE52 (BO, E [E00959308]).
Notes. Following the key in Kiew et al. (2016) the hairs on the upper leaf surface of
our Kalimantan collections diagnose them as belonging to the quite widespread and
variable Begonia calcarea.
Begonia congesta Ridl., J. Straits Branch Roy. Asiat. Soc. 46: 253 (1906); Kiew &
Geri, Gard. Bull. Singapore 55: 116 (2003); Kiew et al., Guide to Begonias of Borneo
82 (2015). – TYPE: Malaysia, Sarawak, Bau, H.N. Ridley s.n. (not located). (Fig. 4)
Distribution. The Kuching limestone in Sarawak (Kiew & Geri, 2003) and Berawat’n
Waterfall in West Kalimantan (Fig. 2).
Fig. 1. Habit of Begonia bayae S.Julia & Kiew, photographed in Betung Kerihun National
Park, West Kalimantan, with male ower shown in the inset. (Photos: M. Ardiyani).

Gard. Bull. Singapore 72(1) 2020
36
Fig. 2. Distribution of Begonia bayae S.Julia & Kiew, B. calcarea Ridl., B. congesta Ridl., B.
dimorpha S.Julia, B. edgariana S.Julia & Kiew, B. magnicarpa C.W.Lin & C.I Peng and B.
paoana Kiew & S.Julia in Borneo, showing the localties for the new records of these species
in Kalimantan. Distribution data available from Hughes et al. (2015, continuously updated).

37
New species and records of Begonia from Kalimantan
Fig. 3. Begonia calcarea Ridl. A. Habit. B. Male ower buds. C. Female ower after
pollination. D. Petiole and subtending shoot and stipule. E. Leaf showing hairs on upper surface.
F. Pollinated female ower and fruit. G. Petiole and lamina underside. A, B, C & F from
WEKBOE52, Umbo; D, E & G from WEKBOE3, Tikalong waterfall. (Photos: M. Hughes).

Gard. Bull. Singapore 72(1) 2020
38
Fig. 4. Begonia congesta Ridl. A. Habit. B. Upper leaf lamina. C. Mature fruits. D. Male
portion of the inorescence. E. Female ower. All photos from WEKBOE184, Berawan
waterfall (Photos: M. Hughes).

39
New species and records of Begonia from Kalimantan
Specimen examined. INDONESIA: West Kalimantan: Bengkayang Regency, Berawat’n
Waterfall, 10 December 2017, Dilot et al. WEKBOE 184 (BO, E [E00959313]).
Notes. Our collection from Berawan waterfall is a very good match for the illustration
in Kiew et al. (2015), showing the diagnostic characters of quite thick tepals on the male
ower, and distinct tertiary venation on the upper leaf surface. The male inorescence
is also very compact (Fig. 4D), matching the protologue.
Begonia danumensis Chong, Sandakania 20: 57 (2015). – TYPE: Malaysia, Sabah,
Lahad Datu District, Danum Valley Conservation Area, Nature Trail, 26 July 2014,
Chong et al. 156802 (holotype SAN; isotypes K, KEP, SAR, SING, SNP). (Fig. 5)
Distribution. Found in the Danum Valley Conservation Area (DVCA) in Sabah, and
also around Gua Tewet in Bengalon, East Kalimantan. It is described as one of the
most common Begonia in the DVCA by Chong et al. (2015), and we noted it formed
quite large colonies near the trails around Gua Tewet (Fig. 8).
Specimens examined. INDONESIA: East Kalimantan: Bengalon, Gua Tewet, 61 m, 26 Nov
2016, Hughes et al. EKBOE84 (BO, E); ibid., 36 m, 27 Nov 2016, M. Hughes et al. EKBOE115
(BO, E).
Notes. Our eld photos and specimens are a good match for material collected from
the DVCA, and for the photos in Chong et al. (2015) and Kiew et al. (2015: 94 & 95).
The Kalimantan specimens lack dentate tepals in the female owers, and have slightly
more elongate male inorescences, but we consider this to be acceptable within-
species variation as the populations are fairly disjunct.
Begonia dimorpha S.Julia, Sandakania 20: 59 (2015). – TYPE: Malaysia, Sabah,
Lahad Datu, Danum Valley, Borneo Rainforest Lodge, Cofn Trail, 27 July 2014,
Chong et al. SAN157257 (holotype SAN; isotypes KEP, SAR, SING, SNP). (Fig. 6)
Distribution. Danum Valley in Sabah on alluvial soils and around Karangan in East
Kalimantan on limestone karst (Fig. 2).
Specimens examined. INDONESIA: East Kalimantan: Karangan, karst forest on edge of MPI
plantation, 19 Nov 2016, Hughes et al. EKBOE03 (BO, E); Karangan, karst block, 22 Nov
2016, Hughes et al. EKBOE46 (BO, E); Karangan, isolated karst block, 22 Nov 2016, Hughes
et al. EKBOE49 (BO, E); Karangan, Baay village [cultivated], Wilkie et al. PWE1124 (BO, E).
Notes. In Kalimantan this species is only recorded from limestone, which differs from
the type locality. Our collections and eld observations in the Karangan area showed
a range of tepal number in the male owers (2, 3 and 4); the type has 2 tepals. There
is a similarity between Begonia dimorpha and the earlier described B. tawaensis Merr.
(also from the Tawau Hills) which requires further investigation.

Gard. Bull. Singapore 72(1) 2020
40
Fig. 5. Begonia danumensis Chong. A. Habit. B. Female ower. C. Male portion of
inorescence. D. Female owers. E. Ripe fruit. F. Male ower. A & B from EKBOE115, C–F
from EKBOE84, both collections from the trail leading from Gua Tewet basecamp in Bengalon,
East Kalimantan. (Photos: M. Hughes).

41
New species and records of Begonia from Kalimantan
Fig. 6. Begonia dimorpha S.Julia. A. Habit. B. Fruits on thin pedicels. C–E. Male owers
showing variation in tepal number. F. Female ower. G. Male inorescence. H. Habit during
owering phase showing horizontal spreading and smaller leaves. A & F from EKBOE3, B,
C, D, E, G & H from EKBOE46, all from Karangan, East Kalimantan. (Photos: M. Hughes).

Gard. Bull. Singapore 72(1) 2020
42
Begonia edgariana S.Julia & Kiew, Phytotaxa 252(1): 25 (2016). – TYPE: Malaysia,
Sarawak, Batang Ai, Sungai Bebiyong Besai, 112°4'0"E 1°19'0"N, 2 August 2015, J.
Sang et al. 2758 (holotype SAR; isotypes BRUN, KEP, SNP).
Distribution. Batang Ai National Park in Sarawak and in Serawai (Sintang Regency)
in West Kalimantan (Fig. 2).
Specimen examined. INDONESIA: West Kalimantan: Serawai, Uut Labang, 112°38'56"E
0°36'6"N, 6 Oct 1995, Church et al. 2227 (E [E00754271]).
Notes. The diagnostic characters for this species are the pseudo-opposite leaves which
are densely hairy above; it is illustrated in Sang & Kiew (2016: 26).
Begonia jamiliana Rimi, Sandakania 20: 178 (2015). – TYPE: Malaysia, Sabah,
Tawau District, Tawau Hills Park, near by the Head Ofce and along the trail to the
Mt. Lucia, 4 March 2004, Rimi SNP A 16607 (holotype SNP; isotype SAN). (Fig. 7)
Distribution. Tawau Hills National Park, Sabah, and around Karangan in East Kutai,
East Kalimantan (Fig. 8).
Specimens examined. INDONESIA: East Kalimantan: Karangan, Air Tujun, 1°28'49"N
117°37'32"E, 21 Nov 2016, Hughes et al. EKBOE24 (BO, E); Karangan, Air Tujun, 1°28'57"N
117°37'45"E, 21 Nov 2016, Hughes et al. EKBOE32 (BO, E); Karangan, Segara Indochem
logging concession, Km 38, near Sungai Nyuaring, 9 Dec 2016, Wilkie et al. PWE1104 (BO,
E [E00973799]) & PWE1105 (BO); Karangan, Segara Indochem logging concession, Km 0,
forest next to entrance to logging concession, 10 Dec 2016, Wilkie et al. PWE1112 (BO, E).
Notes. Our eld observations and photographs are a very good match for the images
in Kiew et al. (2015: 130), with the mbriate white bracts with a pink edge at the base
of the female owers being particularly distinctive. The collections from Kalimantan
had either all male or all female owers; species in this group often show a prolonged
single gender owering phase and although may appear dioecious are not (Kiew, pers.
comm).
Begonia magnicarpa C.W.Lin & C.I Peng, Taiwania 62: 237 (2017). – TYPE:
Malaysia, Sarawak, Sri Aman, Lubok Antu, Batang Ai, 120 m, pressed from cultivated
plant, 8 July 2014, C.W. Lin 566 (holotype SAN). (Fig. 9)
Distribution. Batang Ai National Park in Sarawak, and Betun Kerihun National Park
and Tikalong waterfall in West Kalimantan (Fig 2).

43
New species and records of Begonia from Kalimantan
Fig. 7. Begonia jamiliana Rimi. A. Habit. B. Leaf undersides. C. Male ower. D. Pollinated
female ower with persistent tepals. E. Female ower. A–C from EKBOE24, D & E from
EKBOE32, from the Karangan Air Tujun in East Kalimantan. (Photos: M. Hughes).

Gard. Bull. Singapore 72(1) 2020
44
Fig. 8. Distribution of the new species B. bawangensis Girm., Randi & M.Hughes.,
B. pendulina Girm. & M.Hughes and B. recurvata Girm. & M.Hughes and the distribution of
new records for B. danumensis Chong, B. jamiliana Rimi, B. padawanensis C.W.Lin & C.I
Peng and B. zygia C.W.Lin & C.I Peng in Kalimantan. Distribution data available from Hughes
et al. (2015, continuously updated).
Specimens examined. INDONESIA: West Kalimantan: Bengkayang Regency, Tikalong
District, Tunang Village, Tikalong Waterfall, 2 Dec 2017, Girmansyah et al. WEKBOE 2 (BO,
E [E00959306]); Betung Kerihun National Park, Sungai Rantaugong, 23 Dec 2011, Ardiyani
et al. 622 (BO); Betung Kerihun National Park, Sungai Rantaugong, 24 Dec 2011, Ardiyani et
al. 630 (BO).
Notes. A close relative of Begonia stenogyna Sands from Brunei, differing in having
larger leaves and fruit (up to c. 6 cm long) and glabrous stems.

45
New species and records of Begonia from Kalimantan
Fig. 9. Begonia magnicarpa C.W.Lin & C.I Peng. A. Habit. B. Female ower. C. Male
inorescence. D. Female ower and ovary. All from WEKBOE2, Tikalong waterfall. (Photos:
M. Hughes).

Gard. Bull. Singapore 72(1) 2020
46
Begonia padawanensis C.W.Lin & C.I Peng, Nord. J. Bot. 33: 558 (2015); Yiing
et al., Phytotaxa 381(1): 19 (2018). – TYPE: Malaysia, Sarawak, Kuching District,
Padawan, 01°07′N, 110°16′E, 200 m, 28 August 2013, C.W. Lin 559 (holotype SAR;
isotypes HAST, KEP, TAIF).
Distribution. The foothills of Gunung Penrissen in Sarawak, and Serimbu District,
Landak Regency, West Kalimantan (Fig. 8).
Specimen examined. INDONESIA: West Kalimantan: Serimbu, Tenguwe, en route from Gua
Endagah to Gunung Cermin, 600 m, 29 Dec 1991, Okada & Komara 31748 (L).
Notes. A lithophyte on wet rocks or near waterfalls, with distinctive spathulate leaves.
Begonia paoana Kiew & S.Julia, Gard. Bull. Singapore 58: 217 (2007); Kiew et al.,
Guide to Begonias of Borneo 198 (2015); Sang et al., Sandakania 20: 97 (2015). –
TYPE: Malaysia, Sarawak, Gunung Rimo, 110°16'37"E 1°19'1"N, April 2006, J. Sang
et al. S91390 (holotype SAR; isotypes E, KEP, L, SING). (Fig. 10)
Distribution. Kuching Division, Sarawak, on the Padawan-Serian limestone and
Kubah National Park (Sang et al., 2015b), and in the foothills of Gunung Bawang and
Gunung Niut in Bengkayang Regency, West Kalimantan (Fig. 2.).
Specimens examined. INDONESIA: West Kalimantan: Sintang Regency, Areal Plasma Nutfa
Tegua Tibun, 0°40’N 110°58’E, 20 Oct 2000, Albertus & Sisiyasa 2278 (WAN); Bengkayang
Regency, Seluas District, Sahan Village, Umbo, Gunung Niut, 6 Dec 2017, Girmansyah et al.
WEKBOE 25 (BO, E); ibid., 7 Dec 2017, Girmansyah et al. WEKBOE 47 (BO, E [E00959316]);
ibid., 7 Dec 2017, Girmansyah et al. WEKBOE 50 (BO, E [E00959318]); Bengkayang
Regency, Seluas District, Sahan Village, Umbo, Mabeh river, base of Mt. Niut, 8 Dec 2017,
Girmansyah et al. WEKBOE 99 (BO, E [E00959321]); ibid., 8 Dec 2017, Girmansyah et al.
WEKBOE 113 (BO, E [E00959315]); ibid., 8 Dec 2017, Girmansyah et al. WEKBOE 122
(BO, E); Bengkayang Regency, Sungai Betung District, Suka Bangun Village, along trail to Mt
Bawang, 13 Dec 2017, Girmansyah et al. WEKBOE 122 (BO, E).
Notes. This species is very close to Begonia lailana Kiew & Geri, with our collections
from Kalimantan blurring the boundaries between the two species hitherto considered
endemic to Sarawak. The key couplet in Sang et al. (2015b) differentiates Begonia
lailana and B. paoana in part using leaf venation characters which unfortunately do
not hold for the images of the two species in Kiew et al. (2015). We have used the
character of truncate versus rounded fruit wings and the larger leaf size to diagnose
our collections as Begonia paoana (however the fruit wing character also does not
differentiate the images of B. paoana and B. lailana in Sang et al., 2015b). The recently
described Begonia minutitepala S.Julia & Kiew (Yiing et al., 2018) is also very closely
allied to these two species, and a revision of material of all three, including molecular
work, would be useful.

47
New species and records of Begonia from Kalimantan
Fig. 10. Begonia paoana Kiew & S.Julia. A. Habit. B. Female ower and ovary. C. Stem and
petioles. D. Mature fruits. E. Female ower. F. Male inorescence. A, D & F from WEKBOE25
and B, C & E from WEKBOE47, both from Umbo. (Photos: M. Hughes).

Gard. Bull. Singapore 72(1) 2020
48
Begonia zygia C.W.Lin & C.I Peng, Taiwania 64 (2): 135 (2019). – TYPE: Cultivated
plant from a nursery in Taiwan, originally collected in Malaysia, Sarawak, Sri Aman
Division, near Nanga Entulang, c. 100 m, vouchered and selected as type on 11 July
2018, C.W. Lin 652 (holotype TAIF; isotype HAST, K). (Fig. 11)
Distribution. Endemic to Borneo, from Sri Aman Division in Sarawak (Lin & Peng,
2019) and Bengkayang Regency in West Kalimantan (Fig. 8).
Specimen examined. INDONESIA: West Kalimantan: Bengkayang Regency, Tujuhbelas
District, Riam Manajur Waterfall, 30 Jul 2019, Randi TCF71 (BO).
Notes. An erect Begonia found in forest on sandstone and near streams or waterfalls.
Our specimens and eld observations show a quite high variation in vegetative
characters, with leaves opposite or alternate, the lamina adaxially bullate to nearly
at, and the plants reaching up to 1 m tall. The pinnate venation with the opposite
branching of the secondary veins is distinctive.
New species
Begonia bawangensis Girm., Randi & M.Hughes, sp. nov. § Petermannia
Differs from the two other species in Begonia sect. Petermannia (Klotzsch) A.DC.
from Borneo with peltate leaves (B. baramensis Merr. and B. nothobaramensis Joffre)
in having ovate leaves (not oblong or broadly lanceolate), male owers with four
tepals (not 2) and persistent white bracts (not green or reddish green and caducous).
– TYPE: Indonesia, West Kalimantan, Bengkayang Regency, Gunung Bawang, 675
m, 13 December 2017, D. Girmansyah et al. WEKBOE187 (holotype BO; isotypes E
[E00959310, E00959311]). (Fig. 12)
Caulescent herb, erect or scrambling on steep (volcanic) rocks. Stem c. 30–50 cm
tall, internodes 3–8 cm long. Stipules ovate to lanceolate, deciduous, pale green, c.
20 × 9 mm, with scattered miniscule hairs visible with a microscope. Leaves: petiole
terete, eshy, pale green, glabrous, 3–15 cm long; lamina peltate, ovate, pale green
adaxially and milky green abaxially, with a thin chocolate outline on the margin when
young and expanding, bleaching to very pale green in direct sunlight, glabrous on both
surfaces, ovate, 10–15 × 6–9 cm, very asymmetric, point of petiole attachment c. 5 mm
from the lamina margin; venation palmate-pinnate, main veins 5–8; margin sinuate
and very shallowly and broadly dentate, dentition more obvious after drying; apex
shortly acuminate, c. 8 mm long. Inorescence terminal erect, 10–15 cm long, slightly
zigzag, pale green to whitish, glabrous, female owers solitary, basal, male owers
10–15, distal; primary peduncle c. 7 cm long, apical peduncles very short making the
male owers very close together; bracts white, translucent, broadly ovate, c. 7 × 6 mm,
trip acute. Female ower with translucent white bracteoles c. 8 mm away from the
base of the ovary; ovary white, with three subequal wings, total size including wings

49
New species and records of Begonia from Kalimantan
Fig. 11. Begonia zygia C.W.Lin & C.I Peng. A. Habit. B. Male inorescence. C. Male ower.
D. Unripe fruit. All from Randi TCF71. (Photos: A. Randi).

Gard. Bull. Singapore 72(1) 2020
50
Fig. 12. B. bawangensis Girm., Randi & M.Hughes. A. Habit. B. Male ower. C. Stipules. D.
Peltate leaf base. E. Bracts and male inorescence. F. Female ower. G. Ovary. H. Immature
fruit. All from WEKBOE187, Gunung Bawang, West Kalimantan. (Photos: M. Hughes).

51
New species and records of Begonia from Kalimantan
c. 20 × 23 mm, apex of wings rounded; capsule ellipsoid, white with slightly pale
green at apex, three-locular, with bid placentae; tepals 5, white, glabrous, ovate, c. 8
× 4–7 mm, base and apex rounded, outer 2 larger; styles 3, free to the base, shallowly
Y-shaped, yellow, stigmatic surface once spiralled. Male ower with 4 white glabrous
tepals, outer larger, ovate to sub-orbicular, c. 10 × 8 mm, base cordate, apex rounded,
inner elliptic, c. 7 × 2 mm, base and apex obtuse; androecium with c. 13 stamens
arranged on a short column, laments c. 0.25 mm, anther c. 1 mm long, hooded, slits
on the abaxial side, c. 0.5 mm. Fruit shape as for the ovary, total size c. 23 × 26 mm
including wings, pale green and recurved at maturity with the largest wing facing
downwards.
Distribution. Endemic to the western ank of Gunung Bawang in Bengkayang
Regency, West Kalimantan, where it is found in a narrow altitudinal band of around
675–725 m, growing on a wet near-vertical basalt rock seep face, in dipterocarp forest
(Fig. 8).
Etymology. After the type locality of Gunung Bawang, a mountain named after its
distinctive shape like a bulb of garlic (bawang in Indonesian).
Provisional IUCN conservation assessment. Gunung Bawang has the status of a
protection forest and the population of Begonia bawangensis is about 1.5 km inside the
boundary (data from Salim, 2015). However a logging chute was found constructed at
the base of the mountain during our 2017 expedition, and illegal logging is ongoing.
The site of the population is so steep that logging is unlikely in the immediate vicinity,
however further degradation of the forest could alter the hydrology of the site. Based
on the assumption that Begonia bawangensis is a single-site endemic, and that ongoing
logging indicates a projected decline in the quality of habitat, we consider a category
of Critically Endangered to be appropriate, under criteria B2ab(iii) (IUCN Standards
and Petitions Subcommittee, 2017).
Notes. Among other Bornean Begonia, the leaf shape of B. bawangensis is closest to B.
serapatensis Kiew & S.Julia, although it does not appear to be closely allied (also the
leaves of B. serapatensis are basixed). The persistent showy white bracts are unusual,
and the afnity of this species is not clear.
Begonia pendulina Girm. & M.Hughes, sp. nov. § Petermannia
Similar to Begonia dimorpha in having fruits with equal wings pendent on a long thin
pedicel from horizontal owering stems, but differs in having oblong-elliptic leaves
(not ovate-lanceolate), ovary capsule globose (not ellipsoid), fruit with a truncate
apex (not wings ascending) and petioles with sparse bristles (not glabrous). – TYPE:
Indonesia, East Kalimantan, Karangan, Gua Tapah Tangan, 55 m, 20 November 2016,
M. Hughes et al. EKBOE8 (holotype BO; isotype E [E00983717]). (Fig. 13)

Gard. Bull. Singapore 72(1) 2020
52
Fig. 13. Begonia pendulina Girm. & M.Hughes. A. Habit. B & C. Female owers in pairs.
D. female ower. E. Ripe fruits on thin pedicels. F. Unripe fruit. G. Male ower. H. Male
inorescence. I. Lamina sinus. All from EKBOE8, Gua Tapah Tangan in Karangan, East
Kalimantan. (Photos: M. Hughes).

53
New species and records of Begonia from Kalimantan
Caulescent erect herb on limestone. Stems c. 80 cm tall, many, glabrous, internodes c.
10 cm long at the base, shortening to c. 1 cm near the apex when owering. Stipules
oblong-lanceolate, 15–20 × 7 mm, pale green, deciduous, apex caudate. Leaves: petiole
terete, eshy, red, with sparse bristles (obvious in living plants, but scarcely visible on
dried material), 1.5–4 cm long; lamina basixed, dark green above, reddish below,
glabrous above with sparse bristles on main veins below, oblong-elliptic, 7–18 × 2–6.5
cm, asymmetric, base cordate with a gap in the sinus, lobes overlapping in living
material; venation palmate-pinnate, main veins 8–10; margin shallowly and sparsely
dentate to denticulate; apex acute to shortly acuminate. Inorescence 8–12 cm long,
female owers borne singly or in pairs, rarely in threes, basal, male owers c. 50,
apical, arranged in cymes from a racemose axis; bracts ovate, c. 6 × 4 at the base of the
inorescence, becoming smaller towards the apex, translucent, tip rounded, quickly
deciduous. Female ower without bracteoles; ovary green to reddish on the wings,
wings 3, equal, total size including the wings c. 10 × 23 mm, apex of wings triangular,
capsule globose, three-locular, with bid placentae; tepals 5, glabrous, white with a
pink blush at the base, ovate, entire or sparsely denticulate, 6–8 × 11–13 mm, outer 2
larger; styles 3, free to the base, Y-shaped, yellow, stigmatic surface twice spiralled.
Male ower with 2 tepals, glabrous, orbicular, c. 7 × 7 mm, pink with a white margin,
androecium with c. 45–50 stamens on a short column, laments 1 mm, anther 0.75
mm, hooded, slits on the abaxial side, c. 0.5 mm. Fruit shape as for the ovary, total size
c. 12 × 30 mm including wings, pendulous on a 3–4 cm hair-like pedicel.
Distribution. Endemic to limestone in the East Kutai Regency in East Kalimantan,
known from two localities, Gua Tapah and Batu Tamiang. Grows on steep karst in the
shade, at an altitude of 55 to 75 m (Fig. 8).
Etymology. After the fruits which hang on long thin pedicels (Latin pendulinus,
meaning hanging down).
Provisional IUCN conservation assessment. Both Gua Tapah and Batu Tamiang are
outside the network of protection forest sites in the Sankulirang-Mangkalihat karst
system (data from Salim, 2015); the sites are karst outcrops in a matrix of disturbed
forest and palm oil plantation. Currently, it seems there is no ongoing decline of the
vegetation of the karst blocks themselves, and hence the criteria for CR and EN are not
met. However, as there is no protection for the locality and only two sites are known,
we consider an assessment of Vulnerable (VUD2) to be appropriate, given a future
threat (e.g., limestone mining) could drive the species to being critically endangered
or extinct in a very short time (IUCN Standards and Petitions Subcommittee, 2017).
Additional specimen examined. INDONESIA: East Kalimantan: Karangan, Batu Tamiang,
75 m, 22 Nov 2016, Hughes et al. EKBOE44 (BO, E); ibid., 11 Dec 2016, Wilkie et al. PWE
1211 (BO).

Gard. Bull. Singapore 72(1) 2020
54
Notes. When fruiting, the pendulous capsules which are wider than long are instantly
distinctive. Vegetatively it is very similar to Begonia recurvata Girm. & M.Hughes,
but lacks the distinctive soft puberulent indumentum of that species.
Begonia recurvata Girm. & M.Hughes, sp. nov. § Petermannia
Similar to Begonia propinqua Ridl. in having fruits on stiff, recurved pedicels, differing
in having oblong-elliptic leaves (not ovate) and male owers with 2 tepals (not 4),
and lacking a sticky indumentum. – TYPE: Indonesia, East Kalimantan, Karangan,
Gunung Madu, 37 m, 20 November 2016, D. Girmansyah et al. EKBOE12 (holotype
BO; isotype E [E00983709]). (Fig. 14)
Caulescent erect herb on limestone. Stems c. 30–50 cm tall, puberulent, internodes
c. 9 cm long, becoming shorter toward the apex. Stipules early deciduous, not seen.
Leaves: petiole terete, eshy, red, puberulent, 2–3 cm long; lamina basixed, dark
green above, paler green below with red venation, glabrous above, puberulent on
the veins below, ovate-lanceolate, 10–19 × 4.5–8 cm, asymmetric, base cordate
with a gap in the sinus; venation palmate-pinnate, main veins c. 9; margin broadly
shallowly dentate-sinuate; apex acute to shortly acuminate. Inorescence c. 10 cm
long, female owers basal, borne singly or in pairs along a central axis, with male
owers apical on short cymes; bracts not seen. Female ower without bracteoles;
ovary pale green, wings 3, subequal, total size including the wings c. 15 × 15 mm,
apex of wings triangular, capsule ellipsoid, three-locular; tepals 5, glabrous, white
with pink venation at the base, entire, elliptic, subequal, c. 14 × 5 mm; styles 3, free
to the base, Y-shaped, yellow, stigmatic surface twice spiralled. Male ower with 2
tepals, glabrous, suborbicular, c. 7 × 6 mm, white with pink at the base, androecium
with c. 30 stamens on a short column, laments 1 mm, anther 0.75 mm, hooded, slits
on the abaxial side, c. 0.5 mm. Fruit shape as for the ovary, total size c. 15 × 15 mm
including wings, wings 3–4 mm wide, recurved on a 1.5 cm stiff pedicel with the two
shorter wings uppermost.
Distribution. Endemic to limestone in the East Kutai Regency in East Kalimantan
(Fig. 8), only known from the type locality of Gunung Madu. Grows on steep karst in
the shade, at an altitude of c. 40 m.
Etymology. After the fruits which are on stiff recurved pedicels (Latin recurvatus,
meaning recurved or curved backwards).
Provisional IUCN conservation assessment. Gunung Madu is outside the network of
protection forest sites in the Sankulirang-Mangkalihat karst system (data from Salim,
2015); the site is a karst outcrop in a matrix of disturbed forest and palm oil plantation.
Currently, it seems there is no ongoing decline of the vegetation of the karst blocks
themselves, and hence the criteria for CR and EN are not met. However, as there is no
protection for the locality and only two sites are known, we consider an assessment of

55
New species and records of Begonia from Kalimantan
Fig. 14. Begonia recurvata Girm. & M.Hughes. A. Habit. B. Ripe fruit on recurved pedicel. C.
Female owers. D. Male ower. E. Ripe fruits in pairs at the base of the inorescence. All from
EKBOE12, Gunung Madu, Karangan, East Kalimantan. (Photos: M. Hughes).

Gard. Bull. Singapore 72(1) 2020
56
Vulnerable (VUD2) to be appropriate, given a future threat (e.g., limestone mining)
could drive the species to being critically endangered or extinct in a very short time
(IUCN Standards and Petitions Subcommittee, 2017).
Notes. Of the other cane-like Begonia in the area, B. recurvata is distinct in the softly
puberulent indumentum on the stem and petioles; B. dimorpha is glabrous, and B.
pendulina has a few bristle-like hairs on the petioles.
ACKNOWLEDGEMENTS. The authors would like to thank Helen Yeats, Andre Ronaldo and
Marlina Ardiyani for support and companionship in the eld, and the Davis Expedition Fund of
the University of Edinburgh for funding. The Royal Botanic Garden Edinburgh is supported by
the Scottish Government’s Rural and Environment Science and Analytical Services Division.
We also thank RISTEK Indonesia and the Director of the Research Centre for Biology, LIPI,
for supporting this collaboration (permit 391/SIP/FRP/E5/Dit.KI/XI/2017).
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Appendix 1. A checklist of Begonia species recorded from Kalimantan, Borneo (mainland
Kalimantan only). Vouchers available from the Begonia Resource Centre (Hughes et al., 2015,
continuously updated). In this paper: New record*; new species**.
Begonia baramensis Merr.
B. bawangensis Girm., Randi & M.Hughes **
Begonia bayae S.Julia & Kiew*
Begonia calcarea Ridl.*
Begonia congesta Ridl.*
Begonia danumensis Chong*
Begonia dimorpha S.Julia*
Begonia dolichobracteata Girm.
Begonia dracopelta Ardi
Begonia duhungensis Girm.
Begonia edgariana S.Julia & Kiew*
Begonia fuscisetosa Sands
Begonia inggitiae Ardi & Girm.
Begonia gueritziana Gibbs
Begonia jamiliana Rimi*
Begonia ltahensis Girm.
Begonia magnicarpa C.W.Lin & C.I Peng*
Begonia mentewangensis Girm.
Begonia padawanensis C.W.Lin & C.I Peng*
Begonia paoana Kiew & S.Julia*
Begonia pendulina Girm. & M.Hughes**
Begonia promethea Ridl.
Begonia recurvata Girm. & M.Hughes**
Begonia walteriana Irmsch.
Begonia zygia C.W.Lin & C.I Peng*