Three new species of Boesenbergia (Zingiberaceae) from Sabah, Malaysia

Nyee Fan Lam; Halijah Ibrahim; Yen Yen Sam; Rozainah Mohammad Zakaria; Axel Dalberg Poulsen

doi:10.3897/phytokeys.247.107961

Abstract

Three new species of Boesenbergia, B. bosuangii sp. nov., B. ganaensis sp. nov. and B. gokusingii sp. nov. were discovered in Sabah, Malaysia. Boesenbergia bosuangii is similar to B. stenophylla R.M.Sm. in the narrowly ovate lamina but differs in the shape of the bract and the calyx. Boesenbergia ganaensis is closely allied to B. burttiana R.M.Sm. but differs in the absence of a ligule, the longer petiole, the obtuse leaf base, the acute leaf apex, the bilobed calyx and the anther dehiscing by pores. Finally, B. gokusingii is similar to B. variegata R.M.Sm., by the single leafy shoot but differs in having an unequal, ovate lamina, a cordate leaf base, an acute leaf apex and the anther dehiscing by pores. The three new species are described and illustrated in detail. With the addition of these new species, there are in total 13 species with one variety in Sabah.

Key words

Biodiversity, Borneo, endemic, new species, wild gingers

Introduction

The genus Boesenbergia was initially classified in the tribe Hedychieae in the family Zingiberaceae (Burtt and Smith 1972). Considering molecular data, Boesenbergia was subsequently placed in the tribe Zingibereae, subfamily Zingiberoideae (Kress et al. 2002). Eight species from the genus Haplochorema and five species from the genus Caulokaempferia were added to the genus Boesenbergia (Mood et al. 2014; Mood et al. 2020) and there are currently 99 species of Boesenbergia (Lam et al. 2022).

The character, which distinguishes Boesenbergia from all other Zingiberoideae genera, is that the first flowers appear at the top of the inflorescence and flowering progresses towards the base (Poulsen and Searle 2005; Sakai and Nagamasu 2006, 2009; Mood et al. 2020). The flowers are usually white or pale yellow or orange with a spoon-shaped labellum ornamented with red and/or pink. The diagnostic characters of Boesenbergia in Sabah are the growth form (creeping or erect), number of leave per shoot (1 to many), anther dehiscence (slits or pores), length of petiole, and shape of the lamina, including base and apex (Lam 2023).

Borneo harbours approximately 38 species of Boesenbergia (Smith 1987; Ibrahim 1992; Sirirugsa 1992; Poulsen 1993; Larsen 1997; Cowley 1998, 2000; Larsen et al. 1999; Saensouk and Larsen 2001; Sakai and Nagamasu 2006, 2009; Lamb et al. 2013; Lam et al. 2022) of which only 10 species and one variety have been reported in Sabah (Lam et al. 2022). The distribution pattern of the species within Sabah is poorly known but they seem to be usually found in riverine, limestone, and near waterfalls in primary forests. Therefore, this study is focused on revealing the species diversity of Boesenbergia in Sabah.

Materials and methods

Field collections were made between August 2016 and August 2017 at Ranau and Kimanis Districts. The morphology of the new species was analyzed using living plants with reference to herbarium materials (E, K, KEP, KUL, SAN and SING). The procedures of the fieldwork and measurements were conducted based on Lam et al. (2022).

Information collected during fieldwork and herbaria was recorded in the Taxon Data Information Sheet (TDIS) form. The form consist of five sections, namely, taxon attributes, geographic range and demographic details on population (Chua et al. 2010). Ground points of collections were used in the IUCN Red List assessments (IUCN 2022). The assessments of Extent of occurrence (EOO) and Area of occupancy (AOO) and maps were plotted with GeoCAT (Bachman et al. 2011).

Key to the species of Boesenbergia in Borneo (modified from Sakai and Nagamasu 2009)

1	Creeping; leafy shoots normally single-leaved; inflorescence more or less sessile; anther dehiscing by slits	2
–	Erect; leafy shoots with one to many leaves; inflorescence sessile or long pedunculate; anther dehiscing by slits or pores	7
2	Lamina more or less circular, obtuse or obscurely emarginate at apex	*B. orbiculata*
–	Lamina elliptic or narrowly ovate, acute at apex	3
3	Lamina plain green	4
–	Lamina variegated	5
4	Floral tube pubescent outside; flower not red at throat; labellum entire	*B. flavoalba*
–	Floral tube glabrous outside; flower red at throat labellum bilobed	*B. flavorubra*
5	Petiole 2–3 cm long; lamina 7–12 by 2.5–7 cm, dark green with a band of lighter green up the midrib, variegation sometimes extending to the main lateral veins	*B. variegata*
–	Petiole < 0.5 cm long; lamina shorter than 9 cm with width less than 5.5 cm	6
6	Lamina 4–8 by 1.5–2 cm, mid-green with a broad silver band on either side of the midrib above, surface glabrous	*B. kerbyi*
–	Lamina 8.6 by 5.5 cm, upper surface undulating from green to dark green	*B. gokusingii*
7	Fertile shoot single-leaved, rarely bladeless or 2- or 3-leaved	8
–	Fertile shoot with two or more leaves	12
8	Lamina 50 by 12 cm or larger	*B. grandifolia*
–	Lamina much smaller, not exceeding 30 cm long	9
9	Base of the lamina deeply cordate	*B. cordata*
–	Base of the lamina ± attenutate	10
10	Petiole 17–34 cm long	*B. bruneiana*
–	Petiole not exceeding 17 cm	11
11	Lamina 7–12 cm wide; petiole robust ca. 5 mm thick; lamina with appressed hairs especially around midrib below	*B. lambirensis*
–	Lamina less than 7 cm wide; petiole slender, 2 mm or less thick; leaves glabrous	*B. ischonosiphon*
12	Lamina large, much longer than 30 cm	13
–	Lamina shorter than 30 cm, if longer narrower than 7 cm	17
13	Leaf base thickened with outermost bracts forming a bucket or vase-like structure enclosing inflorescence sometimes together with sheaths of upper leaves; petiole 42–50 cm long	*B. jangaruni*
–	Leaf base or sheaths not thickened as above, long-attenuate forming a winged petiole less than 25 cm long	14
14	Anther dehiscing by subapical pores or slits	15
–	Anther dehiscing by pores	16
15	Inflorescence densely pubescent; anther ca. 3 mm long, dehiscing by subapical pores	*B. hosensis*
–	Inflorescence glabrous, anther ca. 10 mm long, dehiscing by longitudinal slits ca. 6 mm long	*B. armeniaca*
16	Leaf sheath sparsely hairy or glabrous; bracts 5–8 cm; floral tube 8–10 cm; ovary glabrous	*B. grandis*
–	Leaf sheath densely hairy; bracts 2–3.5 cm long; floral tube ca. 5.5 cm long; ovary densely hairy in upper half	*B. lysichitoides*
17	Inflorescence long exserted from the leaf sheaths when fully grown, spindle-shaped; flowers red and white	*B. pulchella*
–	Inflorescence never long exserted or spindle-shaped; flower colours various	18
18	Leaves linear; arrangement of blades strongly flabellate	19
–	Leaves elliptic, narrowly ovate or rarely linear to narrowly ovate; arrangement of blades never flabellate	20
19	Flower plain yellow; anther dehiscing by apical pores; bracts 3.5–6.5 cm	*B. flabellata*
–	Flower white, yellow in the centre, pink at the base; anther dehiscing by slits; bracts < 3 cm	*B. burttiana*
20	Leaves variegated	21
–	Leaves plain green	25
21	Leaves bullate, dark green around main veins and almost silvery on raised area	*B. hutchinsonii*
–	Leaves smooth with a silverish or light green central cloud	22
22	Petiole never exceeding 3 cm, lamina narrowly obovate with attenuate base	*B. hirta*
–	Petiole usually much longer than 3 cm, lamina narrowly ovate to elliptic with cuneate base	23
23	Leaves with a silvery cloud; flowers yellow, labellum orange-spotted	*B. ornata*
–	Leaves with yellow central cloud; flowers orange or white with some yellow and reddish purple	24
24	Leaves 5–12 by 3–4 cm; flower orange, darker at base of labellum; anther dehiscing throughout its entire length	*B. aurantiaca*
–	Leaves 18–23 by 4–6 cm flower white with some yellow and reddish purple; anther dehiscing by apical pores, or anther dehiscent only in upper 2/3	*B. belalongensis*
25	At least a few uppermost leaf sheaths thickened and forming a cup-shaped structure	26
–	Leaf sheath not thickened as above	27
26	Innermost leaf sheaths enclosing inflorescence much shorter and wider than outer ones; leaves drying darkish brown	*B. laevivaginata*
–	All leaves with more or less equal laminae; leaves green or grey-green when dry	*B. urceoligena*
27	Anther dehiscing by slits throughout their length	28
–	Anther dehiscing by pores	32
28	Petiole < 8 cm	*B. imbakensis*
–	Petiole > 10 cm	29
29	Calyx unilaterally incised (split on one side)	30
–	Calyx tubular	*B. sugudensis*
30	Lamina wider than 4 cm	31
–	Lamina less than 4 cm wide	33
31	Petiole up to 4 cm long; lamina longer than 10 cm	32
–	Petiole to 2 cm long; lamina 5.2–6.5 by 3.4–3.6 cm	*B. truncata*
32	Lamina 13–16 cm long	*B. apiculata*
–	Lamina at least 11.5 by 5.5 cm	*B. ganaensis*
33	Lamina narrowly ovate, more than 12 cm	34
–	Lamina slightly ovate much shorter, up to 12 cm long, if longer, petiole much shorter than 7 cm	35
34	Lamina 12–20 by 1.5–3 cm; petiole usually to 7–8 cm	*B. stenophylla*
–	Lamina 19 by 3 cm; petiole usually at least 10.5 cm	*B. bosuangii*
35	Leaf sheath and ligule hirsute	*B. parva*
–	Leaf sheath and ligule almost glabrous	36
36	Flower yellow-orange	*B. oligosperma*
–	Flower white and yellow, occasionally red in throat	*B. subulata*

Taxonomy

Boesenbergia bosuangii N.F.Lam, sp. nov.

urn:lsid:ipni.org:names:77349804-1

Figs 1, 2

Diagnosis

The new species resembles B. stenophylla in having a narrowly ovate lamina, but differs in the shape of the bract (linear elliptic vs. cymbiform) and a tubular calyx (vs. tridentate) (Table 1).

Table 1.

Download as

CSV

XLSX

Distinguishing morphological characters of B. bosuangii and B. stenophylla.

Characters	B. bosuangii	B. stenophylla
Plant height	to 30 cm	To about 42 cm
Petiole	7.5 cm	10–18 cm
Leaf apex	Acuminate	Slightly acuminate
Bracts	2.7 cm, linear elliptic, pubescent	4 × 4.5 cm, cymbiform, glabrous
Calyx	2-lobed, pubescent	3-lobed, glabrous
Labellum	Yellow band from base in the centre spreading towards apex, faint red at base and dark red bands bordering the yellow band, obovate, 1.2 × 0.8 cm	White with yellow centre, flabelliform, 2.5 × 2 cm
Lateral corolla lobe	White, 1 × 0.25 cm	Pale yellow, 1.5 × 0.4 cm,

Figure 1.

Boesenbergia bosuangii A habit B spike with one open flower C stamen, ventral view D flower E Bract, bracteole, calyx, epigynous gland, corolla lobes, staminodes, labellum, floral tube with stamen. (Photograph of Lam Nyee Fan 337; Photos: Lam Nyee Fan).

Type

Malaysia. Borneo. Sabah. Cultivated at Kipandi Park, Moyog, 05°54.68'N, 116°06.27'E, 700 m elevation, 8 August 2016, Lam Nyee Fan 356 (holotype BORH!, isotype SAN). Original material collected by Linus Gokusing (BS-23) at Marakau, Gana-gana, Ranau, Sabah, 06°12.24'N, 116°46.03'E, 480–500 m elevation, 3 August 2010.

Figure 2.

Boesenbergia bosuangii Lam N.F., sp. nov. A habit B bract C bracteole D calyx E epigynous glands, F spike with one open flower G flower H stamen, ventral view (Drawing by Lam Nyee Fan). Scale bars: 5 cm (A); 1 cm (B, C, D, E, F, G); 5 mm (H).

Description

Terrestrial, evergreen, herb. Rhizome fibrous, subterranean, ca. 1 cm in diameter with 7 cm internodes, white to light brown, base ca. 0.6 cm in diameter, roots white, up to 18 cm long. Leafy shoots 29.5 cm tall, with 1–2 leaves, with 2–3 outer leafless sheaths, 6.0–6.5 × 0.7–1.1 cm, purple brownish, glabrous. Ligule ca. 0.55 cm long, caudate, brown, glabrous. Petiole 6–7.5 cm long, canaliculate, green, reddish at base. Lamina narrowly ovate, 17–17.4 × 2.5–2.75 cm, erect, dark green above, pale green beneath, glabrous, base attenuate, margin entire, apex acuminate, with acumen ca. 2 mm. Inflorescence ca. 2.8 cm, peduncle 1–2 cm, with up to 6 flowers arranged in a one-sided spiral, one flower open at a time. Fertile bracts linear elliptic, ca. 2.7 cm long, white, reddish at apex, pubescent, margin entire, apex attenuate. Bracteole elliptic, ca. 2 × 0.75 cm, translucent, pubescent, margin entire, apex acute. Flower white, born singly from each bract; calyx 1 cm long, tubular, 2-lobed, translucent, pubescent on both surfaces; corolla tube ca. 3.6 cm long, ca. 1.5 mm wide at base, lobes white, glabrous throughout, dorsal lobe ovate-oblong, ca. 1.1 × 0.5 cm, linear elliptic, concave, white, glabrous, apex acute, lateral lobes ovate, ca. 1.0 × 0.25 cm, oblong, glabrous, apex rounded; labellum, obovate, ca. 1.2 cm × 0.8 cm curved-backward, longer than corolla lobes, with yellow band from base in the centre spreading towards lip, faint red at base and dark red bands on both sides, glabrous; lateral staminodes white, reddish at base, linear, ca. 0.6 × 0.25 cm, glabrous; stamen white throughout, ca. 0.45 cm long, filament ca. 4 mm × 1 mm (widest at base), pubescent, anther ca. 0.5 × 0.3 cm, glabrous, anther crest ca. 0.5 × 2 mm, bilobed, pubescent, thecae oblong, ca. 0.3 × 0.1 cm, glabrous, dehiscing by pores; ovary ca. 4 × 1.5 mm, stigma cup-shaped, glabrous; epigynous glands, two, ca. 0.45 cm long, linear, apex truncate, white. Fruit not seen.

Distribution

Endemic to Borneo, Sabah.

Other specimens seen

Malaysia. Sabah. Telupid District, Taviu Forest Reserves, c. 200 m elevation, lowland forest, 17 May 2001, Sundaling D, SAN142970 (SING!, SAN!).

Etymology

The species is named after Dr. Steven Bosuang, owner of Kipandi Park. He is an entomologist doing conservation efforts on insects and plants of Sabah. His collaborations with local and overseas scientist produced many research papers and reports for the conservation of Sabah.

Ecology

Riverine area in mixed dipterocarp forest, 50–300 m elevation, flowering in August.

Conservation status

Vulnerable VU D1. Boesenbergia bosuangii is endemic to Sabah. This species is found at Ranau and Telupid Districts. Due to the small, restricted populations outside protected area and possible threats from development, landslides and flooding, this species is assessed as VU (Fig. 3).

Figure 3.

Distribution map of Boesenbergia bosuangii, EOO = 0 km², AOO = 8 km² (Bachman et al. 2011).