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Three new species of Loxocarpus (Gesneriaceae) from Sarawak, Borneo

Authors:
289
Gardens Bulletin Singapore 67(2): 289–296. 2015
doi: 10.3850/S2382581215000241
Three new species of Loxocarpus (Gesneriaceae)
from Sarawak, Borneo
T.L. Yao
Forest Research Institute Malaysia,
52109 Kepong, Selangor, Malaysia
yaotzeleong@frim.gov.my
ABSTRACT. Three new species, Loxocarpus burttii T.L.Yao, Loxocarpus littoralis T.L.Yao
and Loxocarpus segelamensis T.L.Yao are described from Sarawak, Malaysia.
Keywords. Borneo, Gesneriaceae, Loxocarpus, new species, Sarawak
Introduction
Loxocarpus R.Br. is a small genus consisting of 20 species distributed in Sumatra,
Peninsular Thailand, Peninsular Malaysia and Borneo. The genus was previously
included in Henckelia Spreng. (Weber & Burtt, 1998; Banka & Kiew, 2009) but was
reinstated by Middleton et al. (2013) based on earlier phylogenetic studies (Weber
et al., 2011). The species of Loxocarpus from Peninsular Malaysia were revised (as
Henckelia sect. Loxocarpus) by Banka & Kiew (2009), although since then Yao et al.
(2012) have described a new species from Kelantan. Loxocarpus is most diverse in
Borneo, represented by nine species, and here a further three species are described.
All new species described here have a relatively long capsule (10–17.5 mm
long). Loxocarpus was principally characterised by a short plagiocarpic capsule less
than 10 mm long (Banka & Kiew, 2009). However, molecular phylogenetic studies
(Yao, 2012) support the inclusion of several long-capsuled species which had been
placed in Didymocarpus Wall. and Henckelia.
Loxocarpus burttii and L. segelamensis belong to the ‘saintpaulioid’
morphological group (Yao, 2012) which is conned to Borneo. Species in this group
resemble Saintpaulia H.Wendl. (Gesneriaceae) and are characterised by their at-
faced corolla with a pair of exposed stamens. The short campanulate corolla with
deltoid lobes observed in L. littoralis is shared with L. argenteus B.L.Burtt and L.
pauzii T.L.Yao. All three new species are known only from a single locality each and
L. segelamensis and L. littoralis are represented only by the type specimen.
New species
Loxocarpus burttii T.L.Yao, sp. nov.
This species is similar to Loxocarpus verbenios (C.B.Clarke) B.L.Burtt in its
290 Gard. Bull. Singapore 67(2) 2015
relatively long capsules (10–12 mm long vs 9–20 mm long) and its usually ovate or
elliptic lamina, but differs in its buff trichomes (not silvery) and adpressed trichomes
along the petiole (vs spreading in L. verbenios). – TYPE: Borneo, Sarawak, Miri
District, Lambir Hills National Park, below Bkt. Lambir, sandstone cliff, c. 1500 feet,
24 September 1978, Burtt B11597 (holotype E; isotypes KEP, SAR). (Fig. 1, 2)
Rosulate herb with numerous crowded leaves. Rootstock woody, 2–4(–9.5) cm long,
4–6 mm thick; trichomes buff, adpressed, dense; adventitious roots long, wiry. Petiole
base of withered leaves persistent. Stem lacking or distinctive, 1–2 cm long. Leaves
alternate, crowded at the top; trichomes dense, buff, adpressed on petiole, equally
dense on lamina above and beneath. Petiole relatively thick, (0.8–)2.8–3.8 cm long,
0.7–1.1 mm diam., grooved above; longest petiole about equal in length to the lamina.
Lamina dark green above, paler beneath, moderately thick, ovate or elliptic or obovate,
(2.5–)3.3–4.1 × (0.8–)1.3–1.5 cm; base cuneate, equal, margin entire or undulate,
apex acute or blunt; midrib and veins obscure above, inconspicuous beneath, lateral
veins 3 pairs. Inorescence axillary, a reduced cyme with a single ower; trichomes
buff, eglandular, shaggy, dense on peduncle and bracts; mixed with shorter glandular
trichomes on pedicel. Peduncle slender, 4.5–6.5 cm long; bracts narrowly lanceolate,
c. 1.5 × 0.3 mm, apex blunt; pedicel 0.5–0.9 mm long. Flower trichomes buff and
eglandular, shaggy and dense on the outer surface of the calyx, less dense, shorter
and erect on the outer surface of the corolla; dense on the ovary. Calyx green, upper
lip 3-lobed, lower lip 2-lobed; lower lobes larger than the upper lobes, tube c. 0.6
mm long, c. 1 mm wide, lobes deltoid, apex acute, c. 1.4 mm long, base c. 0.5 mm
wide. Corolla mauve, at-faced, tube very short, c. 0.6 mm long, c. 1.1 mm wide;
upper lip with 2 lobes c. 2.5 × 2.5 mm, lower lip with 2 lateral lobes c. 2.3 × 2 mm
and a median lobe c. 3 × 2.3 mm; lateral and median lobes oblong. Fertile stamens 2,
yellow; anthers projecting beyond corolla tube, exposed; laments straight, thickened
in distal half, c. 2.2 mm long; anthers coherent only at the ventral tip, kidney-shaped, c.
1.7 × 0.7 mm; staminodes 3, club-shaped. Nectary absent. Ovary narrowly conical or
slightly oblique, c. 1.8 mm long, c. 1 mm wide; style curved upwards near the stigma,
c. 3 mm long; stigma capitate, exposed. Capsule long slender conical, 10–12 mm
long, 1.1–1.4 mm wide, style c. 1.5 mm long, sub-persistent; valves straight, splitting
dorsally to form a trough; trichomes a mix of eglandular and glandular trichomes,
adpressed to erect. Seeds not seen.
Distribution. Borneo, Sarawak, known only from Lambir FR, Bukit Lambir.
Habitat. Hill forest at c. 460 m asl. On sandstone cliffs or on acidic sandy soil.
Etymology. This species is named after the collector of the type, B.L. Burtt (1913–2008),
a British botanist who collected extensively and is well known for his contributions to
the taxonomy of the Old World Gesneriaceae.
291
Three new Loxocarpus from Borneo
Fig. 1. Distribution map of Loxocarpus burttii T.L.Yao (), L. littoralis T.L.Yao () and L.
segelamensis T.L.Yao ().
Additional specimens examined. MALAYSIA: Sarawak: Bukit Lambir, 23 Oct 1993, Ali & La
Frankie AI 191 (SING [SING106370]); ibidem, 25 Oct 1993, Ali & La Frankie AI 192 (SING
[SING106371]); ibidem, 2 Nov 1976, Ilias & Yeo S.38365 (K, KEP [KEP60951], SAR).
Note. A handwritten annotation by Burtt on the folder of the specimen selected here
as the holotype mentioned that it is possibly a new species and listed S.38365 as
conspecic.
292 Gard. Bull. Singapore 67(2) 2015
Fig. 2. Loxocarpus burttii T.L.Yao. A. Habit. B. Leaf. C. Corolla opened to show stamens.
D. Bracts, calyx, ovary, style and stigma. E. Stamens. F. Staminode. Drawn by N. Mohamad
Aidil from (A, B) Burtt B11597, and (C–F) Ilias & Yeo S.38365.
293
Three new Loxocarpus from Borneo
Loxocarpus littoralis T.L.Yao, sp. nov.
This species has a relatively long capsule similar to that of Loxocarpus violoides
(C.B.Clarke) T.L.Yao (17 mm long vs 15–30 mm long) but differs in the dense
spreading woolly trichomes on the lamina upper surface (not thin adpressed), grooved
upper surface of the petiole (not terete), deltoid corolla lobes (not oblong) and conical
capsule (not cylindric). – TYPE: Borneo, Sarawak, Kuching District, Tanjung Po,
in deep shade on dripping wet rocks near the sea, 5 October 1955, Brooke 10614
(holotype L [L645488]). (Fig. 1)
Rosulate herb. Rootstock woody, to 1 cm long, c. 3 mm thick or lacking; rootstock with
buff trichomes; adventitious roots long, wiry. Petiole base of withered leaves caducous.
Stem lacking. Leaves alternate, crowded at the top of the rootstock; trichomes buff,
woolly and shaggy, dense on lamina above and less dense beneath. Petiole slender,
c. 2 cm long, c. 1 mm thick, grooved above; longest petiole shorter than the lamina.
Lamina moderately thick, ovate or broadly ovate, c. 2.5 × 1.7 cm; base cuneate or
rounded, equal, margin shallowly serrate, apex blunt; midrib and veins obscure above,
distinct beneath, lateral veins 3 pairs. Inorescence axillary, a reduced cyme with a
single ower; trichomes buff, shiny. Peduncle slender, c. 5 cm long; bracts narrowly
lanceolate, c. 3 × 0.5 mm, apex acute; pedicel c. 3 mm long. Flower: corolla violet,
tube short with deeply dissected lobes; upper lip with 2 upper lobes, lower lip with 2
lateral lobes and a median lobe; upper lobes smaller, lateral and median lobes larger,
lobes recurved, deltoid. Capsule long, slender conical, c. 17 mm long, c. 2.5 mm wide;
valves straight, splitting dorsally to form a trough. Seeds not seen.
Distribution. Borneo, Sarawak, known only from the type specimen from Tanjung Po
(Bako NP).
Habitat. On dripping wet rocks near the sea in deep shade.
Etymology. It is named for its seashore habitat.
Note. There is only one fully opened ower on the type specimen which I decided not
to dissect, thus preventing a fuller description of the calyx and corolla lobes. More
material is needed.
Loxocarpus segelamensis T.L.Yao, sp. nov.
This species is similar to Loxocarpus violoides in the relatively long capsule (17.5
mm vs 15–30 mm long) and in the ovate laminas, but differs in its buff trichomes (not
silvery), the longer lamina (c. 7.4 cm long vs up to 5.5 cm), and the presence of c. 10
inorescences in ower at any one time, with each inorescence bearing 3–7 owers
(vs 1–2 inorescences per plant, bearing 1 or rarely 2 owers). TYPE. Borneo,
Sarawak, Marudi District, Baram, Sungai Segelam, around Long Selatong Lepo Ga’,
on rocky ridge, 24 July 1977, Chin 2797 (holotype KLU [KLU29970]). (Fig. 1, 3)
294 Gard. Bull. Singapore 67(2) 2015
Fig. 3. Loxocarpus segelamensis T.L.Yao. A. Habit. B. Leaf. C. Corolla opened to show
stamens. D. Calyx, ovary, style and stigma. E. Anthers. F. Staminode. G. Capsule. Drawn by
N. Mohamad Aidil, all from Chin 2797.
295
Three new Loxocarpus from Borneo
Creeping herb with buff, shiny trichomes, stem decumbent. Rootstock c. 6 cm long,
c. 2 mm thick; trichomes adpressed, dense; adventitious roots wiry. Petiole base of
withered leaves persistent. Erect stem distinct, c. 8 cm long. Leaves alternate, below
well-spaced, crowded at the top; trichomes adpressed, dense on petiole, on lamina
above and beneath dense. Petiole slender, c. 6 cm long, terete; longest petiole about
equal in length to the lamina. Lamina dark green above, paler beneath, thin, ovate, c.
7.4 × 2.9 cm; base cuneate, equal, margin nely serrulate, apex acuminate or acute;
midrib and veins obscure above, distinct beneath, lateral veins 4(–5) pairs, lowermost
pair arising from lamina base. Inorescences axillary, a reduced cyme with a single
ower or once branched, c. 10 per plant, owers 3–7; trichomes eglandular, adpressed
on peduncle, bracts and pedicel. Peduncle slender, 10.5–11.5 cm long; bracts linear, c.
4.4 × 0.4 mm, apex acuminate; pedicel to 1.2 mm long. Flower trichomes eglandular,
adpressed on calyx, outer surface of the corolla and ovary, dense. Calyx green, upper
lip 3-lobed, lower lip 2-lobed; lower lobes larger than the upper lobes, tube c. 1 mm
long, c. 1.9 mm wide, lobes linear-lanceolate, apex thickened, blunt, c. 3.9 mm long,
base c. 1 mm wide. Corolla pale blue, at-faced, tube very short, c. 1.8 mm long,
c. 2.9 mm wide; upper lip with 2 lobes c. 7 × 3.8 mm, divided to the base, lower
lip with 2 lateral lobes, c. 5.6 × 3.5 mm and a median lobe c. 4.8 × 3 mm, lobes
deeply divided; lateral and median lobes oblong. Fertile stamens 2, yellow; anthers
projecting beyond the corolla tube, exposed; laments straight, thickened in the distal
half, c. 4.5 mm long; anthers coherent only at the ventral tip, kidney-shaped, c. 2.5 ×
1.4 mm; staminodes 3, the two lateral club-shaped, the central a minute protrusion.
Nectary absent. Ovary conical, slightly oblique, c. 2.8 mm long, c. 1.8 mm wide; style
straight, c. 2.3 mm long; stigma capitate, exposed. Capsule slender cylindric, c. 17.5
mm long, c. 1.9 mm wide, style sub-persistent; valves straight, splitting dorsally to
form a trough; trichomes eglandular, adpressed, dense. Seeds not seen.
Distribution. Borneo, Sarawak, known only from the type specimen from Ulu Long
Selatong.
Habitat. On rocky ridge.
Etymology. It is named for its type locality, Sungai Segelam.
ACKNOWLEDGEMENTS. These new species were discovered during the course of my
studies for a Master of Science degree at the University of Malaya, Kuala Lumpur, Malaysia.
I am grateful to R. Kiew (KEP) and N.W. Haron (University of Malaya) for their guidance
throughout my study. I thank the Training Committee of the Forest Research Institute Malaysia
for sponsoring my study for the rst two years, and the Institute of Research Management
and Monitoring, University of Malaya for the provision of a research grant (PS173-2008B).
I gratefully acknowledge the curators at E, K, KEP, KLU, L, SAN, SAR, SING and SNP for
granting me permission to examine specimens in their care. I thank R. Kiew, D.J. Middleton
and an anonymous reviewer for their constructive comments on the manuscript.
296 Gard. Bull. Singapore 67(2) 2015
References
Banka, R.A. & Kiew, R. (2009). Henckelia section Loxocarpus (Gesneriaceae) in Peninsular
Malaysia. Edinburgh J. Bot. 66: 239–261.
Middleton, D.J., Weber, A., Yao, T.L., Sontag, S. & Möller, M. (2013). The current status of the
species hitherto assigned to Henckelia (Gesneriaceae). Edinburgh J. Bot. 70: 385–404.
Weber, A. & Burtt, B.L. (1998 [‘1997’]). Remodelling of Didymocarpus and associated genera
(Gesneriaceae). Beitr. Biol. Panzen 70: 293–363.
Weber, A., Middleton, D.J., Forrest, A., Kiew, R., Lim, C.L., Radah, A.R., Sontag, S., Triboun,
P., Wei, Y.G., Yao, T.L. & Möller, M. (2011). Molecular systematics and remodelling of
Chirita and associated genera (Gesneriaceae). Taxon 60(3): 767–790.
Yao, T.L. (2012). A Taxonomic Revision of Loxocarpus (Gesneriaceae). Unpublished M.Sc.
thesis. Kuala Lumpur: University of Malaya.
Yao, T.L., Kiew, R. & Haron, N.W. (2012). Loxocarpus pauzii (Gesneriaceae), a new species
from Peninsular Malaysia. Blumea 57: 134–135.
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