Cylindrolobus chienii (Orchidaceae), a new species from Central Highlands of Vietnam

 Taiwania 65(3): 272‒276, 2020 DOI: 10.6165/tai.2020.65.272

Cylindrolobus chienii (Orchidaceae), a new species from Central Highlands of Vietnam

Van Canh NGUYEN1, Leonid V. AVERYANOV2, Van Khuong NGUYEN3, Thi Thanh Dat PHAM4,5, Tatiana V. MAISAK2, Ba Vuong TRUONG6,*

1. Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh Duong Province, Vietnam. E-mail: nguyenvancanh@gmail.com

2 Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia. E-mail: av_leonid@mail.ru

3. Tay Nguyen University, Le Duan, Buon Ma Thuot, Dak Lak Province, Vietnam. Email: nguyenkhuongbanme@gmail.com
4 Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh

Duong Province, Vietnam.
5. Department of Biotechnology, Nong Lam University, Ho Chi Minh City, Vietnam. E-mail: phamthithanhdat@gmail.com
6. Institute of Tropical Biology, Department of Biological Resources, Vietnam Academy of Science and Technology, 85 Tran Quoc

Toan Street, District 3, Ho Chi Minh City, Vietnam. *Corresponding author’s email: bavuong2019@yahoo.com

(Manuscript received 6 March 2020; Accepted 7 May 2020; Online published 12 May 2020)

ABSTRACT: The orchid species new for science, Cylindrolobus chienii (Orchidaceae) discovered on Chu Mu Mountain, M’Drak District, Dak Lak Province of southern Vietnam is described and illustrated. It morphologically close to C. gloensis and C. bidupensis but differs from them in glabrous 2-flowered inflorescence, calli on labellum and character of the lip indumentum.

KEY WORDS: Cylindrolobus bidupensis, C. gloensis, Endemism, Eria, Plant taxonomy.

INTRODUCTION

The genus Cylindrolobus Blume comprises 60–70 species spreading in Southeast Asia from East Himalaya and southern China to New Guinea (Chen et al., 2009; Ormerod, 2014; Ng et al., 2018; Ya et al., 2019). Cylindrolobus was firstly established by Blume in 1828 and regarded as a section of Eria Lindley in 1858. As reported by Pridgeon et al. (2005) Cylindrolobus was included into Callostylis Blume. According to Ng et al., 2018 by molecular studies suggested section Cylindrolobus as separate genus, characterized by multi nodded, erect stems, leaves on apex, short inflorescences, relatively large floral bracts, bearing one or few flowers with subglobose mentum (Wood et al., 2011).

The genus Cylindrolobus in Vietnam (previously Eria sect. Cylindrolobus) included 7 species e.g. C. bidupensis (Gagnep.) Schuit., Y.P. Ng & H.A. Pedersen, C. biflorus (Griff.) Rauschert, C. carunculosus (Gagnep.) Schuit., Y.P. Ng & H.A. Pedersen, C. dacrydium (Gagnep.) Schuit., Y.P. Ng & H.A. Pedersen, C. foetidus (Aver.) Schuit., Y.P. Ng & H.A. Pedersen, C. truncatus (Lindl.) Rauschert, C. clavicaulis (Wall. ex Lindl.) Rauschert. With the newly discovered plant and the combination, the number of Cylindrolobus in Vietnam increases up to 9 species.

MATERIALS AND METHODS

The measurements and description of Cylindrolobus chienii are based on living plants collected in the field. Besides herbarium voucher specimens, additional material was preserved in 70% ethanol and stored at VNM Herbarium (Institute of Tropical Biology, Ho Chi Minh City). Terminology for the morphological description follows Beentje (2012).

TAXONOMIC TREATMENT

Cylindrolobus Blume, Fl. Javae, Praef.: 6 (1828)
Type: Cylindrolobus compressus (Blume) Brieger in

F.R.R. Schlechter, Orchideen Beschreib. Kult. Zücht., ed. 3, 1(11–12): 664 (1981).

Cylindrolobus chienii Vuong, Aver., V.C. Nguyen & T.T.D. Pham, sp. nov. Figs. 1–3

Described from the Central Highlands of Vietnam. Type. VIETNAM, Chu Mu Mountain, M'Drak District, Dak Lak Province, in tropical evergreen forest at elevation 1000–1200 m on granite rocks, 16 February 2020, Nguyen Van Canh, Pham Thi Thanh Dat, Truong Ba Vuong, BV 514 (Holotype: VNM 00023605!).

Description. Herb lithophytic, with several stems densely clustering on short plagiotropic rhizome. Stems erect, terete, distally slightly thickened, to 28 cm long, 0.8–1 cm in diameter, with 8–11 nodes. Leaves 3–4, on apical part of stem, lanceolate, 10–14.5 cm long, 1.8–2 cm wide, acute. Inflorescence axillary, glabrous, 6–7 mm long, peduncle 4–6 mm long, rachis ca. 1 cm long, 2-flowered; floral bracts dark yellow, ovate to broadly 2-flowered; floral bracts dark yellow, ovate to broadly ovate, with 7-veins, 0.6–1.3 cm long, 0.8–1 cm wide, apex rounded; pedicel and ovary reddish brown 1–1.2 cm long. Flowers not widely opening. Sepals outside white with light purple tint, petals and lip white. Dorsal sepal narrowly ovate, 10–12 mm long, 5–6 mm wide, apex obtuse, with 5 veins; lateral sepals narrowly ovate, strongly oblique, 8–12 mm long, 5–6 mm wide, apex obtuse, with 5 veins, connate with column foot forming short sub-globose mentum. Petals oblong lanceolate, slightly oblique, 7–12 mm long, 4–5 mm wide, blunt to roundish at apex, with 3 veins. Lip 3-lobed, ca. 7 mm (from base to tip of lateral sepals), 7 mm wide (at the widest part) attached to the column foot by short claw; side lobes erect, narrowly ovate, falcate, ca. 6 mm long, 2 mm wide, acute to obtuse; median lobe small, 1 mm long and wide, broadly ovate, truncate, slightly down curved, densely hairy with long stiff white glandular hairs; disc with large fleshy, shortly hairy, bi-carinate callus coming distally from the lip base and rising in apical quarter into fleshy bilobulate plate (T-shaped in cross section). Column ca. 4 mm tall, laterally with narrow papillose wings; column foot upcurved ca. 7 mm

long, forming almost right angle with column, at apex with prominent pink papillose knob. Anther cap white, ca. 1 mm long, 2 mm wide, hemispheric, helmet-shaped, finely papillulose, at front with slightly protruding apex and 2 rounded lateral valves; stigma obovate; rostelum shorly protrucing, narrowly ovate, apex subacute; pollinia dull yellow, 8 in 4 pairs, broadly obovate.

Etymology. The species epithet refers to the name of the plant discoverer, Mr. Pham Van Chien. The Vietnamese name is Nỉ Lan Chiến (nov.).

Habitat, phenology and conservation status. Lithophytic clustering herb growing on mossy vertical cliffs in primary evergreen forests on granite at elevations 1000–1200 m a.s.l. Very rare. Flowers in February – March. Estimated IUCN Red List status - DD.

Distribution. Endemic of southern Vietnam (Chu Mu Moutain, M'Drak district, Dak Lak Province).

Studied specimen (Paratype): VIETNAM, Chu Mu Mountain, M'Drak District, Dak Lak Province, in tropical evergreen forest at, elevation around 1000–1200 m on granite rocks, 16 Feb. 2020, Nguyen Van Canh, Pham Thi Thanh Dat, Truong Ba Vuong, BV 515 (VNM 00023606!).

Notes. The new species may be compared with C. gloensis from India (Agrawala & Ormerod, 2014). However, it distinctly differs from C. gloensis in glabrous scape, rachis, pedicels and flowers (vs. scape, rachis, pedicels and flowers pubescent), short inflorescence ca. 1.6 mm long (vs. 16 mm long), 2- carinate callus rising distally into prominent bilobulate plate T-shaped in cross section (vs. callus on the disc 2- carinate, turn into half-discoid callus on epichile); prominent knob-like papillose callus at column foot apex (vs. column foot with no distinct callus). The new plant also looks similar to C. bidupensis but clearly differs in 2-flowered distinctly lateral, inflorescences 6–7 mm long (vs. inflorescence regularly with more than 2 flowers, subterminal, to 6 cm long), 2-carinate callus forming distally (at base of mid lobe) fleshy bilobulate plate, T-shaped in cross section (vs. disc with 2 separate keels and one median papillous or hairy cushion), median lobe with dense long stiff white hairs (vs. median lobe subglabrous, with dense long stiff white hairs).

Currently Cylindrolobus chienii is known from only one location in Chu Mu Mountain (M'Drak District, Dak Lak Province of southern Vietnam). As no more special field studies were undertaken and no one more populations were found this species may be preliminarily assessed as a species with insufficient data on its distribution and unclear conservation status (Data Deficient) according to IUCN criteria (IUCN Standards and Petitions Committee, 2019).

Cylindrolobus lactiflorus (Aver.) Vuong, Aver., V.C. Nguyen, comb. nov. – Eria lactiflora Aver., Lindleyana 14: 219 (1999).

Artificial key for the genus Cylindrolobus Blume in Vietnam

1a. Plant with several inflorescences along the stem ................. 2 1b. Plant with only terminal or subterminal inflorescence ............. 3 2a. Sepals outside glabrous, lip with two lateral glossy longitudinal

calli with short additional median callus near the apex, epichile

margin papillose ............................................... C. biflorus 2b. Sepals outside pubescent, lip with two lateral longitudinal calli insignificant at the base, raising to the apex, with short additional median lamella, epichile margin with densely stiff white hairs ....... .................................................................... C. foetidus 3a. Median lobe of the lip, small ........................................... 4 3b. Mid lobe of the lip distinct ............................................. 7 4a. Lip with longitudinal calli .............................................. 5 4b. Lip without longitudinal calli .......................................... 6 5a. Pedicel finely pubescent, median lobe glabrous, 2 longitudinal unbroken calli glabrous, distally swollen, disc with hairy median callus .......................................................... C. truncatus 5b. Pedicel glabrous, median lobe pubescent, 2 longitudinal calli broken into two pair of “tear drop” calli, disc with densely villose median callus .............................................. C. dacrydium 6a. Lip median lobe glabrous, at apex with two lateral pubescent calli and small fleshy median cushion ..................... C. carunculosus 6b. Lip median lobe with long stiff white glandular hairs, at apex with short hairs and prominent 2-carinate callus .................. C. chienii 7a. Lip with 3 longitudinal calli covered by dense stiff and glandular hairs .......................................................... C. lactiflorus 7b. Lip with 2 longitudinal glabrous calli and median hairy keel ..... 8 8a. Lip with 2 low longitudinal glabrous Calli on the disc extends from the middle, median callus fat papillose ................. C. clavicaulis 8b. Lip with 2 rather flat longitudinal glabrous Calli on the disc extends from base to middle, median callus hairy ............. C. bidupensis

ACKNOWLEDGMENTS

The authors would like to thanks to Dr. Pankaj Kumar and Mr. Mark Arcebal Naive for their kindly discussion. Field and laboratory studies of 6th author were funded and supported by Herbarium of Institute of Tropical Biology (ITB) Ho Chi Minh City, Vietnam. The work on this research and publication was supported in part by the RFBR “Inventory, taxonomy and geography of the orchids (Orchidaceae) of Vietnam”, 20-04- 00339 А.

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