Novitates Bruneienses, 2. A remarkable new species of Begonia sect. Petermannia (Begoniaceae) from Brunei Darussalam

Abstract

Begonia jamilahana Y.W.Low, Joffre & Ariffin is described and illustrated here as a new species based on a collection from Ladan Hills Forest Reserve, Tutong, Brunei Darussalam. This new taxon is closely related to B. conniegeriae S.Julia & Kiew and B. papyraptera Sands, but differs in a suite of morphological characters. Begonia jamilahana is placed in Begonia section Petermannia, the largest of all the sections recognised.

Full text

61
Gardens’ Bulletin Singapore 67(1): 61–68. 2015
doi: 10.3850/S2382581215000071
Novitates Bruneienses, 2. A remarkable new species of
Begonia sect. Petermannia (Begoniaceae)
from Brunei Darussalam
Y.W. Low1, A.A. Joffre2 & A.K. Muhammad Arifn2
1Herbarium, Singapore Botanic Gardens, National Parks Board,
1 Cluny Road, 259569 Singapore
low_yee_wen@nparks.gov.sg
2Brunei National Herbarium, Forestry Department,
Ministry of Industry and Primary Resources, Jalan Menteri Besar,
Berakas, BB3910 Brunei Darussalam
ABSTRACT. Begonia jamilahana Y.W.Low, Joffre & Arifn is described and illustrated
here as a new species based on a collection from Ladan Hills Forest Reserve, Tutong, Brunei
Darussalam. This new taxon is closely related to B. conniegeriae S.Julia & Kiew and B.
papyraptera Sands, but differs in a suite of morphological characters. Begonia jamilahana is
placed in Begonia section Petermannia, the largest of all the sections recognised.
Keywords. Begonia jamilahana, Begoniaceae, Borneo
Introduction
Begonia is a well-known genus, largely due to its popularity in horticulture. They
are mostly cultivated for their attractive foliage, as well as showy owers (Holttum
& Enoch, 1995; Tebbit, 2005). At present, there are about 1500 species distributed
throughout the tropics, except in Australia, with many more taxa yet to be discovered
as individual species are commonly known to be conned to very small geographical
areas (Tebbit, 2005; Heywood et al., 2007; Hughes, 2008).
Merrill (1921), in his bibliographic enumeration, listed 26 species of Begonia
for Borneo, most of which were endemic species with the exception of B. repens
Blume. The checklist by Hughes (2008) enumerated 95 species for Borneo, all of
which are strictly restricted to the island. For Brunei, Coode et al. (1996) recorded 16
species, namely, Begonia awongii Sands, B. bahakensis Sands, B. baramensis Merr.,
B. bruneiana Sands, B. chlorandra Sands, B. cyanescens Sands, B. eutricha Sands, B.
fuscisetosa Sands, B. hexaptera Sands, B. laccophora Sands, B. leucochlora Sands, B.
leucotricha Sands, B. papyraptera Sands, B. sibutensis Sands, B. stenogyna Sands and
B. temburongensis Sands. Four subspecies were recognised for Begonia bruneiana,
namely B. bruneiana subsp. bruneiana, B. bruneiana subsp. angustifolia Sands, B.
bruneiana subsp. labiensis Sands and B. bruneiana subsp. retakensis Sands. All of
the Brunei begonias were newly described by Sands (1996), with the exception of
Begonia baramensis Merr.

62 Gard. Bull. Singapore 67(1) 2015
A recent collection from the Ladan Hills Forest Reserve reveals yet another
novelty for Brunei from Begonia section Petermannia (Klotzsch) A.DC. as delimited
by Doorenbos et al. (1998). It has the following dening characters of the section,
namely (i) 2-tepaled male owers, (ii) anthers with unilaterally positioned slits, (iii)
5-tepaled female owers, (iv) inorescence protogynous, with 1–2-owered female
inorescences, (v) trilocular ovary with axile placentation and bilamellate placentae,
and (vi) fruits with equal wings. The Ladan Hills novelty is closely related to Begonia
papyraptera, but differs in having (i) a smooth and terete stem in live material, (ii)
scantily scattered translucent hispid hairs on both sides of the leaf lamina, (iii) a mature
upper leaf surface that is dark green with red markings on vein axil nodes nearer to
the base of the leaf, (iv) a pale green lower leaf surface, and (v) base of capsule wings
cuneate. In contrast, Begonia papyraptera has (i) a ribbed and angular stem in live
material, (ii) a leaf lamina that is glabrous on both sides, (iii) a leaf upper surface that
is plain dark green with conspicuous white spots, (iv) a maroon lower leaf surface, and
(v) base of capsule wings rounded. Apart from Begonia papyraptera, the Ladan Hills
taxon is also closely related to Begonia conniegeriae S.Julia & Kiew, but differs in the
characters enumerated in Table 1. Hence, the Ladan Hills taxon is described here as
new.
New species
Begonia jamilahana Y.W.Low, Joffre & Arifn, sp. nov. (sect. Petermannia)
Similar to Begonia papyraptera Sands but differs in having a smooth and terete stem,
leaf blade scantily covered with translucent hispid hairs on both sides, upper mature
leaf surface dark green with red markings on vein axil nodes nearer to the base of
the leaf, lower leaf surface pale green, and base of capsule wings cuneate. – TYPE:
Brunei, Tutong District, Lamunin, Ladan Hills Forest Reserve, Compartment 1, 58
m, 4°42’16”N 114°44’12”E, lowland mixed dipterocarp forest on yellow sandy clay
soils, steep slope, 15 Dec 2010, P. Azlan, A.K. Muhd. Arifn, A. Watu & M. Rauzaidi
BRUN 23373 (holotype BRUN (including spirit material); isotypes K, SING). (Fig. 1,
2)
Cane-like begonia, c. 40 cm tall, most parts of the plant glabrous except for the upper
and lower surface of lamina scantily covered with hispid translucent hairs neatly
arranged in between veins. Stems pale green, 0.8–1.5 cm thick, very succulent, terete,
internodes 2.5–9 cm long, laxly branched, nodes red, not swollen. Stipules dark red,
narrowly lanceolate, c. 1–2 cm long, c. 0.3–0.5 cm wide at the base, keeled, margin
entire, apex acute, caducous. Leaves alternate, oblique, distant, held horizontally;
petioles light green with both ends red, 5–20.5 cm long, terete; lamina dark green with
red markings on vein axil nodes nearer to the base of the leaf and iridescent above, pale
green beneath, young leaves very rarely with small white spots above, fading in older
leaves, asymmetric, elliptic to broadly elliptic, 12–19 × 11.5–14 cm, broad side 8–10.5

63
A new Begonia from Brunei Darussalam
cm wide, base cordate, basal lobes 3.5–7 cm, margin dentate, apex acuminate, acumen
1.5–2 cm long; venation palmate-pinnate, 7–9 veins, each branching dichotomously
2–3 times, vein nodes red near junction of petiole and gradually fading to pale green
towards the margin, at and prominent on the upper surface, raised and prominent
on the lower surface. Inorescences terminal, protogynous; female inorescences
(1–)2-owered, positioned one node below the male inorescences or solitary,
peduncles absent; male inorescences composed up to 4 cymose partial inorescences,
each monochasium with 3–6 owers, peduncles 7–15 mm long. Bracts dark red, ovate,
keeled, c. 0.9–1.1 cm long, c. 0.8 cm wide, margin entire, persistent. Male owers:
pedicel white to pale pink, 7–9 mm long; tepals 2, pale pink with red ushes, ovate-
elliptic, 7–9 × 4–5 mm, margin entire, apex rounded; stamens c. 39, cluster conical,
stalked; laments c. 0.8 mm long; anthers yellow, oblong, c. 1 mm long, apex slightly
emarginate. Female owers: pedicel pale green, 4–6 mm long; ovary pale green, 1.3–2
× 0.3–0.4 cm, wings 3, equal, locules 3, placentae 2 per locule, placentation axile;
tepals 5, pink, outer 4 tepals ovate, c. 18–20 × 8–11 mm, innermost tepal oblanceolate,
c. 10 × 8 mm, margin entire, apex rounded; styles 3, deeply Y-shaped, c. 6 mm long,
divided c. 2 mm from the base; stigma yellow, papillose forming a continuous twisted
band. Capsules (1–)2, pendent, 2.7–30 × 1.5–1.7 cm, pale green when young, brown
when mature, locules 3, wings 3, equal, leathery when fresh, thinly brous when dry,
slightly expanded, tip rounded, dehiscing between locule and wing; pedicel c. 4–6 mm
long.
Additional specimens examined. BORNEO: Brunei: Tutong District, Lamunin, Ladan Hills
Forest Reserve, Ladan Hill, 20 Nov 2014, A.A. Joffre et al. BRUN 24029 (BRUN, SING).
Distribution and habitat. Begonia jamilahana is so far known only from the Ladan
Hills Forest Reserve, where it was documented on steep earth banks and adjacent
slopes in the mixed dipterocarp forest on yellow sandy clay soils.
Etymology. This species is named for Hajah Jamilah binti Haji Abdul Jalil, acting
Deputy Director of the Brunei Forestry Department, upon her retirement in 2015, as
a token of appreciation for her excellent service rendered to the Forestry Department,
as well as her unwavering support for the Brunei-Singapore botanical exploration
programme.
Provisional IUCN conservation assessment. Begonia jamilahana is so far known only
from a single population at Compartment 1, Ladan Hills Forest Reserve. The IUCN
status proposed here is Least Concern (LC) as the species is protected in a forest
reserve with no discernible threats. The Brunei Ministry of Industry and Primary
Resources ofcially announced in 2014 that logging will be phased out in all forest
reserves (Brunei Times, 2014).
Notes. Begonia papyraptera Sands was described in Coode et al. (1996), based on a
single collection from the helipad Landing Point (LP) 286, Batu Apoi Forest Reserve,

64 Gard. Bull. Singapore 67(1) 2015
Table 1. Comparison of morphological characteristics, habitat and distribution among Begonia
conniegeriae S.Julia & Kiew, B. jamilahana Y.W.Low, Joffre & Arifn and B. papyraptera
Sands.
Begonia conniegeriae Begonia jamilahana Begonia papyraptera
Stem (in life),
texture
Smooth and terete Smooth and terete Ribbed and angular
Stem (in life),
colour
Reddish or red brown Pale green with red
nodes
Pale green
Stem nodes (in
life), swollen
Yes No Yes
Upper lamina
surface,
pubescence
Sparsely covered with
translucent erect hairs
Scantily covered with
translucent erect hairs
Glabrous
Upper lamina
surface (in life),
colour and
markings
Dark green Dark green with red
markings on vein axil
nodes near the leaf
base
Dark green with
white spots
Lower leaf
surface,
pubescence
Sparsely covered with
translucent erect hairs
Scantily covered with
translucent erect hairs
Glabrous
Lower leaf
surface (in life),
colour
Pale green Pale green Maroon
Capsule wings,
shape proportion
Unequal Equal Equal
Capsule wing
base, shape
Cuneate Cuneate Rounded
Habitat, substrate Limestone Yellow sandy clay
soils
Unknown
Distribution Lobang Cina, Gunung
Mulu National Park,
Marudi District,
Sarawak, Malaysia
Ladan Hills Forest
Reserve, Tutong
district, Brunei
Darussalam
Batu Apoi Forest
Reserve, Temburong
district, Brunei
Darussalam

65
A new Begonia from Brunei Darussalam
Fig. 1. Begonia jamilahana Y.W.Low, Joffre & Arifn. A. Habit. B. Close-up of upper leaf
surface. C. Detail of stem showing red nodes. D. Close-up of male portion of inorescence.
E. Close-up of female owers. F. Detail of styles showing twisted papillose stigmas. G. Cross
section of an immature fruit. H. Immature fruit (side view). I. Detail of a stipule. A & B from
P. Azlan et al. BRUN 23373, C–J from ex-situ collection at BRUN. (Photos: A & B, A.K.
Muhammad Arifn; C–J, Y.W. Low)

66 Gard. Bull. Singapore 67(1) 2015
Fig. 2. Distribution of Begonia conniegeriae S.Julia & Kiew, Begonia jamilahana Y.W.Low,
Joffre & Arifn, and Begonia papyraptera Sands.
Temburong district (Johns et al. RJ7422), without a detailed description but with a
brief Latin diagnosis as follows:
“a B. congesta Ridley alis fructus latioribus, caulibus plusminusve glabris
(non ‘hirtis’), staminibus 15 vel plus (non 12), tepalis staminibus multo
longioribus (non brevioribus); a B. leucochlora (vide supra) fructus apice
rotundato (non alis acutis et fructus apice truncato), petiolis longioribus
differt.”
A total of three duplicates were gathered, with two sheets indicated as holotype in K
(Sheet 1 of 2: K000761105, and Sheet 2 of 2: K000761106); while the third sheet,
which is an isotype, is lodged in BRUN (herbaria acronyms follow Thiers, continuously
updated). For this study, the two holotype sheets were examined through the Southeast

67
A new Begonia from Brunei Darussalam
Asian Begonia database (Hughes & Pullan, 2007), as well as the JSTOR® Global Plants
website (Global Plants, continuously updated). Detailed examination was carried out
on the isotype preserved in BRUN. In addition, a living plant of Begonia papyraptera
was discovered recently by the second author in cultivation in the ex-situ collection of
begonias at the Kuala Belalong Field Study Centre (KBFSC). This cultivated specimen
in KBFSC matches the type materials represented in K and BRUN and, therefore,
provided us with further insights into the species for this study.
Begonia conniegeriae S.Julia & Kiew was described in Sang et al. (2013). We
have been unable to examine the materials as the isotype indicated in the article as having
been distributed to SING had not arrived by 13 March 2015 (Serena Lee (SING), pers.
comm.). Images of the type materials were also not available for examination either in
the Southeast Asian Begonia database (Hughes & Pullan, 2007) or the JSTOR® Global
Plants website (Global Plants, continuously updated). The morphological characters of
Begonia conniegeriae used in this study are extracted from Sang et al. (2013).
ACKNOWLEDGEMENTS. We are grateful to Haji Saidin bin Salleh, the Director of Forestry
Department, Brunei Darussalam for providing us with eld support and assistance for this study.
Special thanks to Hajah Jamilah binti Haji Abdul Jalil and Noralinda binti Haji Ibrahim for
their encouragement and continuous support and assistance. Dr Ruth Kiew (KEP) kindly made
available translated Latin diagnoses by Dr Mark Coode (K) of all the Begonia species described
by Martin Sands (K) published in Coode et al. (1996) for this study. Various staff members of
the Brunei National Herbarium (BRUN) have kindly helped: Mediana Kampong and Muhd.
Wauddin Zainol Arifn assisted with herbarium materials and database; Watu Awok, Azlan
Pandai, Jangarun Eri and Rauzaidi Mureh provided excellent assistance in the eld, as well
as maintaining the ex-situ research collection. Research funding for YWL is provided by the
National Parks Board, Singapore and the Singapore Botanic Gardens. Christina Soh (Library of
Botany and Horticulture, Singapore Botanic Gardens) kindly helped with missing references.
We are grateful to the two reviewers, Dr Mark Hughes (E) and Dr Daniel C. Thomas (SING),
for their constructive comments in improving this manuscript. This research collaboration is
conducted under the MoU programme “The Botanical Survey of Brunei Darussalam” between
the Brunei Forestry Department, Ministry of Industry and Primary Resources and the National
Parks Board, Singapore.
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