A new species of billolivia (gesneriaceae) from central vietnam

The plant is a small caulescent herb with a long pubescent petiole, obovate to elliptic leaves, a 5-lobed calyx almost divided to base, and a flower-shape which is very similar to other

Phytotaxa 291 (1): 089–093

http://www.mapress.com/j/pt/

Copyright © 2017 Magnolia Press Article PHYTOTAXAISSN 1179-3155 (print edition)

ISSN 1179-3163 (online edition)

https://doi.org/10.11646/phytotaxa.291.1.9

A new species of Billolivia (Gesneriaceae) from Central Vietnam

NGỌC-SÂM LÝ

Department of Biological Resources, Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Trần Quốc Toản road, District 3, Hochiminh City, Vietnam E-mail: samly@itb.ac.vn and lysamitb@gmail.com

Abstract

Billolivia middletonii, a new species from Cà Ðam Mountains, Quảng Ngãi Province, Central Vietnam, is described and

il-lustrated A morphological description, a colour plate, the distribution, ecological information, the conservation status, and

notes to species of Billlolivia in Vietnam are given.

Introduction

The genus Billolivia Middleton et al (2014a: 255) was recently described by Middleton et al (2014a) It comprises at

least eight species of small perennial caulescent herbs growing mostly on sandstone substrates in lowland to montane

evergreen closed forest in Southern Vietnam (Middleton et al 2014a, 2014b, Luu et al 2015, Vũ et al 2015) During botanical investigations in Central Vietnam in 2016, a new lithophytic species of Billolivia was discovered and collected

from Cà Ðam Mountains, Tây Trà district, Quảng Ngãi Province, Vietnam The plant is a small caulescent herb with

a long pubescent petiole, obovate to elliptic leaves, a 5-lobed calyx almost divided to base, and a flower-shape which

is very similar to other species in the genus (see Middleton et al 2014a, Luu et al 2015, Vũ et al 2015) After careful examination of the material from E, P, SING, VNM, VNMN, SING herbaria and comparision to Billolivia species in southern Vietnam, it was confirmed that the plant is new to science and is here described as Billolivia middletonii All

measurements and characters in the description were made from mature, living plants and herbarium specimens The

terminology in general follows Beentje (2010) and Middleton et al (2014a, 2014b) The IUCN assessment uses the

criteria given in IUCN version 3.1 (2012)

Taxonomic treatment

Billolivia middletonii N.S Lý, sp nov.

Similar to B kyi in the long pubescent petioles, the shape of the lamina, and the 5-lobed ovate calyx almost divided to base, but differing

in the glabrous stems (vs densely pubescent), the lamina being glabrous adaxially (vs sparsely pubescent adaxially), much longer bracts, 25–52 mm long (vs shorter, up to 15 mm long), the oblong-obovate corolla lobes with violet lines (vs orbicular, dark to red-purple), the white corolla throats having two yellow patches at base of lower lip, with violet lines (vs dark red with a yellow patch), the longer and pale greenish filaments, 8–10 mm long (vs white with long red patch, 5–6 mm long), fruit 20–25 mm long, ovoid to oblong-ovoid (vs 14–16 mm long, ellipsoid).

TYPE:—VIETNAM Quảng Ngãi Province, Tây Trà District, Trà Trung Commune, Cà Ðam Mountains, Bà Noong stream, 1009 elev., 25

September 2016, Lý Ngọc Sâm, Lý-817 (holotype VNM!, isotypes P!, VNM!) Fig.1 & 2.

Lithophytic, caulescent, perennial herbs with short decumbent stems, robust, to 30 cm long, 1.8–2.2 cm in diam., light brown, with numerous strongly prominent leaf scars, glabrous, except for sparse hairs to 2 mm long at apex in

young plants (Fig.1A, C) Leaves alternate, crowded near stem apex, internodes 0.8–1.8 cm long, with roots at the

nodes near base; petioles fleshy, 9.2–18.5 cm long, 0.5–0.7 cm in diam at the middle, pale greenish, densely covered

in a mixture of long brown hairs to 4.5 mm long and shorter appressed brown hairs toward apex, hairs sparse at base;

lamina thick, coriaceous, slightly unequal, elliptic-obovate to broadly elliptic, 12.5–21.5 × 9–14.5 cm, base obtuse

to somewhat truncate, attenuate when young, apex short acute to slightly obtuse, margin coarsely crenate, slightly deflexed, secondary venation 10–13 veins on each side of midrib, sunken above, strongly prominent below, with weaker intersecondaries veins between, tertiary venation alternate percurrent, adaxial lamina dark green, glabrous, margin ciliate with brown hairs to 2.5 mm long, abaxial lamina glaucous greenish, with sparsely brown hairs to 3 mm long between the veins and densely so with both short and long brown hairs to 3.5 mm long on midrib and venation

(Fig 1D) Inflorescences axillary, single or distichously compound-cymes, peduncle pale brown-red to tinged greenish,

densely short brown pubescent to 1.5 mm long; simple cymes with a peduncle 6.5–13 mm long and 2–3 mm in diam., 6–8-flowered, compound cymes with peduncle 7–13.5 mm long, 3–3.5 mm in diam and second axes 2–6 mm long, 2–3 mm wide in diam., sometimes sessile, 4–8-flowered in each cyme; bracts narrowly ovate, with a longitudinally prominent vein on the outside, outside pale brown-red [pinkish], tinged pinkish-green towards apex, with sparsely short brown pubescence to 1.5 mm long, denser in the middle, inside whitish or greenish, glabrous, apex acute, ciliate, margin ciliate with brown hairs to 2 mm long (Fig 1I–J); basal bracts (25–)32–52 × 7–9 mm, second bracts [of the subtending second cyme] 24–39 × 5–7 mm; pedicels 18–24 mm long, 1.8–2.5 mm diam in the middle, pale

brown-red [pinkish] or greenish, densely brown pubescent to 2.5 mm long Calyx of 5 ± equal lobes, almost divided to base

with connate part < 1 mm long, 21–26 mm long, 3–4 mm wide at widest point, apex acute, margin ciliate, with a

longitudinally prominent vein on the outside, pale brown-red [pinkish] to greenish outside with sparse brownish hairs

of 2 mm long, paler and glabrous inside (Fig 1L) Corolla 21–25 mm long, composed of a narrow tube which slightly

curves downwards in lower ⅓ and slightly flares towards mouth, and a 2-lipped limb, tube and lobes white outside, with dark violet lines from the upper half of the inside of the tube and onto lobes, ventral surface of throat and upper

half of tube with 2 yellow stripes in line with lobe sinuses, upper halves of lobes white (Fig 1K1–K3, M); tube 16–19

mm long, 10–11 mm wide at throat; upper lip 2-lobed, ca 10–12 mm long, sinus between lobes ca 5 mm, lobes 7–11

× 5.5–8 mm; lower lip 3-lobed, c.16–18 mm long, lobes somewhat oblong-obovate, apices rounded, lateral lobes ca

8–12 × 6.5–9 mm, medial lobe 9.5–14 × 6–8 mm; corolla outside glabrous in basal half of tube, with sparse short white hairs in upper half, with short and long hairs on upper part of tube and outside of lobes, tube inside glabrous and

with short glandular hairs on inside basal 2/3 of lobes Stamens inserted at ca 10 mm from corolla base (Fig 1M–N);

filaments ca 8–10 mm long, narrow at base, widening around middle and slightly curved, white at base, pale greenish

towards apex, with dense glandular hairs in upper half; 2 fertile anthers ca 2–3 × 2–3 mm, thecae ± parallel, 2 anthers fused by tips; lateral staminodes minute, ca 1.5 mm long, white, glabrous; medial staminode minute, ± 1 mm long,

white, glabrous Disc bowl-shaped, shallowly 5-lobed, ca 1–1.5 mm high, 2.5–3 mm in diam., white, glabrous Ovary

ca 5.5–6 mm long, 2–3 mm wide at base, white glandular pubescent at apex (Fig 1O); style 6–8 mm long, white,

densely white glandular pubescent throughout with hairs up to 1 mm long; stigma 2-lobed, 1–2 mm long, 1.5–2 mm wide, lobes ca 1 mm long, glabrous Fruits narrowly ovoid to oblong-ovoid, 20–25 × 5–6.5 mm, translucent grey-greenish, with sparse hairs at apex (Fig 1G) Seeds many, ovoid, 0.2–0.3 × 0.2 mm, black.

Distribution and Ecology:—Currently known only from the type locality in the Cà Đam Mountains, where two

subpopulations of mature, flowering and fruiting plants of Billolivia middletonii were found It grows in rocky stream

beds in lower primary sub-montane evergreen broadleaf forest at about 1000 elev It is locally abundant

Phenology:—Billolivia middletonii was observed with mature fruits in late July and in flower and with young

fruits in late September in its natural habitat This would suggest it flowers several times per year with flowering from May to September, and fruiting from July to December

Conservation status:—Critically Endengered (CR B2a,b(ii,iii)) Billolivia middletonii occurs in a single locality

on Cà Ðam Mountains with fewer than 100 individuals and with a total Area of Occupancy of less than < 0.5 km2 Although this species is under the protection of the local authorities of the Department of Forest Protections in Tây Trà and Trà Bồng Districts, Quảng Ngãi Province, the populations are, however, vulnerable and continuing to decline

in area, extent and quality of habitat due to destruction through human activities, such as harvesting of timber and

non-forest products, especially clearing of forest land for Acacia plantations According to the IUCN Red list criteria

(IUCN, 2012), this qualifies it as Critically Endengered (CR B2ab(ii,iii)) which is therefore proposed here

Additional specimens examined (Paratypes):—VIETNAM Quảng Ngãi Province, Tây Trà District, Trà Trung

Commune, Cà Ðam Mountains, Bà Noong stream, 1009 m elev., September 2016, Lý Ngọc Sâm, Lý-816 (VNM!); the same locality, 29 July 2016, Lý Ngọc Sâm, Lý-784 (VNM!); the same locality, 1008 m elev., 25 September 2016, Lý

Ngọc Sâm, Lý-815 (VNM!).

Etymology:—The specific epithet of the new species is named in honour of Dr David J Middleton of the Singapore

Botanic Gardens for his continuing contribution to our understanding of the Gesneriaceae in Asia, including as the first

author on the paper in which the genus Billolivia was first described.

FIGURE 1 Billolivia middletonii A Habit B Lower part of the stem showing axillary inflorescence C Detail of basal stem showing

large leaf scars and infructescence D Detail of plant with infructescence, and close-up of abaxial leaf margin and petiole E Front view of flower F Side view of flower on its single cyme G Longitudinal and cross-section of fruit H Detail of a compound cyme (back view)

I Basal bracts J Upper bracts K1–K3 Detail of flowers (from left): side, below and top views L Outer and inner views of the 5-lobed calyx M Longitudinal section of the flower N Front and side views of stamens O Side and front views of pistils All photographs from the type, Lý-817.

FIGURE 2 Distribution map of Billolivia middletonii in Central Vietnam.

Notes:—The calyx in Billolivia is more or less divided to the base in some species and fused into a tube in others

The species with the calyx divided to base are B kyi Luu & Tran in Luu et al (2015: 362), B minutiflora Middleton et

al (2014a: 258), B poilanei Middleton et al (2014a: 260), B vietnamensis Middleton et al (2014a: 261), and the new

species (Figure 1L) Of these, B kyi and B middletonii differ substantially from the other three species in having much longer petioles to ≥ 9 cm long Billolivia middletonii differs from B kyi in the morphological features noted above

Billolivia middletonii also resembles B longipetiolata Middleton et al (2014a: 256) and B tichii Luu et al in Vũ et

al (2015: 190) in having long pubescent petioles, obovate to elliptic leaves, and ovate calyx lobes Densely pubescent

stems, coarsely dentate margins, elliptic or deltoid lobes of the tubular calyx, corolla lobes being orbicular to deltoid

with violet or red to pink apexes, and glabrous ovaries distinguish these species from B middletonii

The currently known species of Billolivia are found in a relatively small area in the southern Annammite Mountains

on the Ðà Lạt plateau (Lâm Đồng Province) and in Bình Phước and Ninh Thuận Provinces in Vietnam (Figure 2) The

species are small terrestrial herbs and are quite locally endemic (Middleton et al 2014a, 2014b, Luu et al 2015, Vũ et

al 2015) With the new species described here, nine species of Billolivia are now recorded, all of them from Vietnam

The genus, is, however reported for the first time from Quảng Ngãi Province which extends the distribution range of the genus from Southern to Central Vietnam and ca 400 km further north than previously known localities for the genus (see Figure 2) Further field work in the Annamite mountains is necessary to see if the distributional limit of

Billolivia species in Vietnam could be even further to the north

Acknowledgement

This study is supported by grants from the ITB Key Laboratory of Plant Cell Biotechnology (No.09/TH-SHNĐ/17/03/2016) and the International Collaboration Project between Vietnam Academy of Science and Technology, Vietnam and Centre National de la Recherché Scientifique, France (VAST.HTQT.PHAP.02/N16–17) The author is indebted to Hoàng Nghĩa Sơn, the director of the Institute of Tropical Biology (ITB), for his support in continuing my research, to Trần Đại, the deputy head of the Department of Forest Protection (Quảng Ngãi Province) and Nguyễn Quốc Bảo and Phạm Quang Luân (Trà Trung People’s Commune) for issuing permits for the fieldwork, to Nguyễn Trần Vỹ, the head of the department of Biological Resources (ITB) for providing field resources, and to Mr Hồ Ngọc Lang and

Hồ Văn Đạo for their assistance in the field The co-operation of the project staff, Đặng Văn Sơn, Trương Bá Vương,

Ðỗ Đăng Giáp, Trần Trọng Tuấn and Nguyễn Thị Mai Hương, is acknowledged The author is also thankful to David

J Middleton (SING) and to the anonymous reviewers for their constructive comments and language improvements to this manuscript

References

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