Conamomum odorum, A NEW SPECIES OF Zingiberaceae FROM CENTRAL VIETNAM
ACADEMIA JOURNAL OF BIOLOGY 2019, 41(3): 55–59
DOI: 10.15625/2615-9023/v41n3.13671
1Southern Institute of Ecology, VAST, Vietnam
2Khanh Hoa Association for Conservation of Nature and Environment, Khanh Hoa, Vietnam
Received 8 March 2019, accepted 5 June 2019
ABSTRACT
Conamomum odorum is described as a new species from Khanh Hoa Province, Central Vietnam. It is characterized by sweet smell, striate and narrowly elliptic leaf leaves with short petiole and ligule, ovoid congested inflorescence, pubescent calyx, cream corolla lobes, yellow, obovate and reflexed labellum with median red bands at base and hairy ovary. The new species is illustrated with detailed photographs of key characters and morphologically compared to its closest congeners C. pierreanum and C. rubidum. A distribution map of the genus in Vietnam is provided.
Keywords: Conamomum odorum, fragrant, new species, Vietnam, Zingiberaceae.
Conamomum odorum is described as a new species from Khanh Hoa Province, Central Vietnam. It is characterized by sweet smell, striate and narrowly elliptic leaf leaves with short petiole and ligule, ovoid congested inflorescence, pubescent calyx, cream corolla lobes, yellow, obovate and reflexed labellum with median red bands at base and hairy ovary. The new species is illustrated with detailed photographs of key characters and morphologically compared to its closest congeners C. pierreanum and C. rubidum. A distribution map of the genus in Vietnam is provided.
Keywords: Conamomum odorum, fragrant, new species, Vietnam, Zingiberaceae.
INTRODUCTION
Recent phylogenetic study of Alpinieae (Zingiberaceae) has resurrected Conamomum Ridley (1899), a genus with about 10 species distributed from Indochina to Malay Peninsula, Singapore, Sumatra and Borneo (de Boer et al., 2018). In Vietnam, the genus has been known with only one species: C. rubidum (Lamxay & Lý) Škorničková & Poulsen (Lamxay & Newman, 2012; de Boer et al., 2018).
Recent phylogenetic study of Alpinieae (Zingiberaceae) has resurrected Conamomum Ridley (1899), a genus with about 10 species distributed from Indochina to Malay Peninsula, Singapore, Sumatra and Borneo (de Boer et al., 2018). In Vietnam, the genus has been known with only one species: C. rubidum (Lamxay & Lý) Škorničková & Poulsen (Lamxay & Newman, 2012; de Boer et al., 2018).
Within a NAFOSTED-funded project, our
exploration for Zingiberaceae diversity in
Khanh Hoa Province discovered a very
fragrant ginger with yellow flowers that
looked like C. rubidum. After careful
examination of the plant, we conclude that it
is a new Conamomum species which is
described as C. odorum in this paper. The
general plant terminology follows Beentje
(2016). A distribution map of Conamomum species in Vietnam is provided (Fig. 1). The
preliminary IUCN assessment follows the
guidelines of the IUCN Standards and
Petitions Subcommittee (2017).
MATERIALS AND METHODS
The specimen of the new taxon was collected from Hon Vong Phu Mountain, Khanh Hoa Province and determined based on comparison of its morphological characteristics with its close congeners’.
RESULTS AND DISCUSSION
Description of the new species
Conamomum odorum Luu, H. D. Tran & G. Tran, sp. n.
Morphologically closest to Conamomum rubidum in having yellow flowers, radical inflorescence and 3-lobed labellum with reflexed margins, but differs by smaller laminas (25–30 × 3–3.5 cm), shorter petiole (2–4 mm), ovoid inflorescence, fully pubescent bracts, pubescent calyx, cream corolla lobes, slightly 3-lobed and obovate labellum, hairy ovary and longer filament (ca. 13 mm) (vs. 30–45 × 4.5–7 cm laminas, 5–9 mm petiole, obovoid inflorescence, basally pubescent bracts, glabrous calyx, reddish corolla lobes, strongly 3-lobed and reniform labellum, glabrous ovary and 7–8 mm long filament). Clump-forming herb, to 1.2 m tall with 10–24 leaves per pseudostem; rhizome branched, 4–6 mm in diameter, externally green-cream, internally cream; interval between pseudostems 4–8 cm, scales broadly triangular, 10–24 mm long, 14–20 mm wide, brown, papery, apex acute. Pseudostem swollen at base (ca. 2.5 cm diameter), light pink when young then become green; ligule 1–2 mm long, light green, glabrous, apex obtuse; petiole 2–4 mm long, light green; lamina narrowly elliptic, 25–30 × 3–3.5 cm, glabrous, upper surface dark green, striate, lower surface lighter colored, sometimes light purple, base attenuate, apex acute to caudate, cauda ca. 1 cm long, margin entire. Inflorescence ovoid, erectly arising from creeping rhizome, congested; peduncle 4–6 cm long, scale triangular, red at base turning green towards apex, 2–2.5 × ca. 2 cm, sericeous; spike 5–7 × 6–10 cm; bracts ovate, 28–32 × 8–11 mm, cream when young, turning papery brownish at early stage, hairy abaxially, ciliate at margin, bracteole tubular, 22–24 × 7–8 mm, unilateral slit 9–10 mm, 2- toothed, teeth with ciliate hairs. Calyx tubular, 17–19 mm long, ca. 3 mm broad at base, 6 mm broad at apex, pubescent, 3-toothed, teeth 2–4 mm long. Floral tube 25–27 mm long, cream at base, yellow towards apex, glabrous; dorsal corolla lobe oblong, 20–25 × 10–11 cm, cream, glabrous, apex rounded, cucullate; lateral corolla lobes oblong, 23–25 × 6–8 mm, cream, glabrous, apex rounded, slightly cucullate; labellum obovate, ca. 26 mm long, 5 mm broad at base, 16 mm broad at apex,
The specimen of the new taxon was collected from Hon Vong Phu Mountain, Khanh Hoa Province and determined based on comparison of its morphological characteristics with its close congeners’.
RESULTS AND DISCUSSION
Description of the new species
Conamomum odorum Luu, H. D. Tran & G. Tran, sp. n.
Morphologically closest to Conamomum rubidum in having yellow flowers, radical inflorescence and 3-lobed labellum with reflexed margins, but differs by smaller laminas (25–30 × 3–3.5 cm), shorter petiole (2–4 mm), ovoid inflorescence, fully pubescent bracts, pubescent calyx, cream corolla lobes, slightly 3-lobed and obovate labellum, hairy ovary and longer filament (ca. 13 mm) (vs. 30–45 × 4.5–7 cm laminas, 5–9 mm petiole, obovoid inflorescence, basally pubescent bracts, glabrous calyx, reddish corolla lobes, strongly 3-lobed and reniform labellum, glabrous ovary and 7–8 mm long filament). Clump-forming herb, to 1.2 m tall with 10–24 leaves per pseudostem; rhizome branched, 4–6 mm in diameter, externally green-cream, internally cream; interval between pseudostems 4–8 cm, scales broadly triangular, 10–24 mm long, 14–20 mm wide, brown, papery, apex acute. Pseudostem swollen at base (ca. 2.5 cm diameter), light pink when young then become green; ligule 1–2 mm long, light green, glabrous, apex obtuse; petiole 2–4 mm long, light green; lamina narrowly elliptic, 25–30 × 3–3.5 cm, glabrous, upper surface dark green, striate, lower surface lighter colored, sometimes light purple, base attenuate, apex acute to caudate, cauda ca. 1 cm long, margin entire. Inflorescence ovoid, erectly arising from creeping rhizome, congested; peduncle 4–6 cm long, scale triangular, red at base turning green towards apex, 2–2.5 × ca. 2 cm, sericeous; spike 5–7 × 6–10 cm; bracts ovate, 28–32 × 8–11 mm, cream when young, turning papery brownish at early stage, hairy abaxially, ciliate at margin, bracteole tubular, 22–24 × 7–8 mm, unilateral slit 9–10 mm, 2- toothed, teeth with ciliate hairs. Calyx tubular, 17–19 mm long, ca. 3 mm broad at base, 6 mm broad at apex, pubescent, 3-toothed, teeth 2–4 mm long. Floral tube 25–27 mm long, cream at base, yellow towards apex, glabrous; dorsal corolla lobe oblong, 20–25 × 10–11 cm, cream, glabrous, apex rounded, cucullate; lateral corolla lobes oblong, 23–25 × 6–8 mm, cream, glabrous, apex rounded, slightly cucullate; labellum obovate, ca. 26 mm long, 5 mm broad at base, 16 mm broad at apex,
yellow with median red bands at base,
reflexed, trilobed; lateral staminode minute,
linear, ca. 6 mm long, ca. 1 mm broad at base,
acute towards apex, red at base, cream-yellow
at apex, with few glandular hairs at base.
Filament flat, 13 × 2.5 mm, yellow, sometimes
with red tinge at base, anther yellow, ca. 11.5 ×
4.5 mm (including crest), connective tissue full
of glandular hairs; anther crest trilobed, yellow,
glabrous, lateral lobes narrow triangular, ca.
6 × 1 mm, pointing downwards, central lobe
semi-circular, ca. 3 × 3.5 mm; epigynous
glands two, ca. 2 × 1 mm, yellow; ovary ca. 4 ×
3.3 cm, cylindrical, cream, hairy, tri-locular,
axile placentation. Stigma cup-shaped, yellow,
ostiole ciliate; style ca. 33 mm, cream, sparsely
hairy near apex. Fruits not seen (Fig. 2).
Only known from the type locality and
another location in Khanh Vinh District, Khanh Hoa Province (Luu, pers. obs.).
Therefore, Extent of Occurrence (EOO) is not
estimated. Area of Occupancy (AOO) is
estimated at 8 km2. As both sites are located
outside the national and provincial systems of
existing or proposed protected areas and have
been undergoing heavy impacts by
uncontrolled illegal logging, hydropower
dams and deforestation, we propose to rank
this species as CR B2b(iii)c(iv).
Figure 2. Conamomum odorum. A. Habit. B. Rhizome and inflorescences. C. Ligule.
D. Inflorescence. E. Flower dissection. F. Ovary with epigynous glands and anthers
(side and front views) [Photos: Luu Hong Truong]
Typus: VIETNAM, Khanh Hoa Province,
Ninh Hoa District, Ninh Tay Commune, Mt.
Hon Vong Phu, 12o35’51”N, 108o56’40”E,
660 m elevation, 14 April 2013, Luu Hong
Truong, Tran Gioi, Nguyen Thien Tich,
Nguyen The Van KH-907 (holotype SGN!,
isotypes SGN!, PHH!).
Etymology
Luu Hong Truong et al.
Khanh Hoa Province (Luu, pers. obs.). Therefore, Extent of Occurrence (EOO) is not estimated. Area of Occupancy (AOO) is estimated at 8 km2. As both sites are located outside the national and provincial systems of existing or proposed protected areas and have been undergoing heavy impacts by uncontrolled illegal logging, hydropower dams and deforestation, we propose to rank this species as CR B2b(iii)c(iv).
The specific epithet refers to the special fragrance of the whole plant. After the specimens are dried, the odor becomes stronger and lasts for several years in the herbarium specimens.
Khanh Hoa Province (Luu, pers. obs.). Therefore, Extent of Occurrence (EOO) is not estimated. Area of Occupancy (AOO) is estimated at 8 km2. As both sites are located outside the national and provincial systems of existing or proposed protected areas and have been undergoing heavy impacts by uncontrolled illegal logging, hydropower dams and deforestation, we propose to rank this species as CR B2b(iii)c(iv).
The specific epithet refers to the special fragrance of the whole plant. After the specimens are dried, the odor becomes stronger and lasts for several years in the herbarium specimens.
Proposed Vietnamese name Sa nhân thơm.
Ecology and phenology
The new species grows in closed moist evergreen forests at 600–700 m elevations. Flowering was observed in April. Fruiting is expected to appear in May.
Distribution and IUCN preliminary assessment
Ecology and phenology
The new species grows in closed moist evergreen forests at 600–700 m elevations. Flowering was observed in April. Fruiting is expected to appear in May.
Distribution and IUCN preliminary assessment
Notes
The new taxon is morphologically closest to C. rubidum as they share the following characters: radical congested inflorescence, yellow and 3-lobed labellum with reflexed margins. However, they can be distinguished by key morphological differences as shown in the diagnosis and table 1. The shape and color of the labellum in C. odorum may recall those in C. pierreanum Gagnep. from Cambodia (de Boer, 2018; Gagnepain, 1906 & 1908; Lamxay & Newman, 2012) but both species have many different morphological characters (table 1) that make them distinct from each other.
The new taxon is morphologically closest to C. rubidum as they share the following characters: radical congested inflorescence, yellow and 3-lobed labellum with reflexed margins. However, they can be distinguished by key morphological differences as shown in the diagnosis and table 1. The shape and color of the labellum in C. odorum may recall those in C. pierreanum Gagnep. from Cambodia (de Boer, 2018; Gagnepain, 1906 & 1908; Lamxay & Newman, 2012) but both species have many different morphological characters (table 1) that make them distinct from each other.
Acknowledgements: This research is funded
by Vietnam National Foundation for Science
and Technology Development (NAFOSTED)
under grant number 106-NN.03-2016.77.
REFERENCES
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Gagnepain F., 1906. Zingibéracées nouvelles de l’herbier du Muséum. 15e note.
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