Jasminanthes xuanlienensis T.B.Tran & Rodda, 2016

Tran, The Bach, Hai, Do Van, Ha, Bui Thu & Rodda, Michele, 2016, Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam, PhytoKeys 69, pp. 17-22 : 18-20

Jasminanthes xuanlienensis T.B.Tran & Rodda sp. nov. Fig. 1

Type.

Vietnam. Thanh Hoa province: Xuan Lien National Park , 720 m, N19°59'14.6", E104°59'49.1", 22 April 2013, Do Van Hai et al. XL 904 (HN, holotype; HN, isotype) .

Description.

Liana large, up to 10 m long. Stems glabrous, 1.7-2 mm in diameter; internodes 21-23 cm long. Leaves opposite; petiole 1.6-2.6 cm long, 1.5-2 mm in diameter, pubescent with spreading trichomes, lamina variable in shape, elliptic (ovate), 11-15 × 4.1-6.8 cm, with many black spots when dry; adaxial surface glabrous except sparsely pubescent base with spreading trichomes, basal colleters 1-3 each lamina base, ovoid; abaxial surface pubescent, with spreading trichomes; base round to acuminate; apex acuminate with a caudate tip 0.8-1.5 cm long; lateral veins 9-13 pairs. Inflorescences extra-axillary, simple or dichotomous, umbelliform, up to 30-flowered; peduncle 14-18 cm long, 1.3-1.7 mm in diameter, pubescent, trichomes spreading to retrorse. Pedicel 8.5-11.0 mm long, 0.2-0.5 mm in diameter, pubescent with spreading trichomes. Flower bud just before anthesis fusiform, 10.7-13.0 mm long, 1.9-2.9 mm in diameter, apex acuminate, base bulbous. Calyx sepals 5, free; lobes triangular-linear, apex acuminate, 2.5-2.6 × 0.6-1.0 mm, adaxial surface glabrous, abaxial surface pubescent with spreading trichomes; colleters occurring singly between the sepals, ovoid-conical, 0.2-0.3 × 0.1-0.2 mm. Corolla salverform, tube 12.0-14.5 mm long, adaxi ally with 5 pairs of longitudinal lines of retrorse trichomes, abaxially glabrous, throat pubescent, eglandular trichomes 0.36-0.70(-1.34) mm long, lobes elliptic-ovate to triangular, 7.0-8.0 × 3.0-3.6 mm, adaxial surface salmon-pink, abaxial surface greenish-white. Corona staminal; corona lobes arrow-shaped, much reduced and attached to gynostegium lengthwise, c. 1.8 mm high, c. 0.8 mm wide, glabrous. Guide rails 1.7-2.0 mm long. Gynostegium 3.5-4.0 mm tall, 1.8-2.0 mm wide. Pollinia erect, oblong, 0.49-0.58 mm × 0.2-0.23 mm; caudicle 0.12-0.13 mm × 0.05-0.06 mm; corpusculum rhomboid, 0.2-0.23 × 0.10-0.11 mm. Anther appendages erect, covering the style head, 1.0-1.2 × 0.7-0.9 mm. Style head conical with a round tip, 0.8-1.0 mm high. Ovary bi-carpellate, carpels ovoid, c. 1.60 mm long, 1.10 mm wide at the base. Fruits and seeds not observed.

Etymology.

The species is named after the type locality, Xuan Lien National Park, Thanh Hoa province, in northern Vietnam.

Distribution and ecology.

Jasminanthes xuanlienensis was found growing in primary evergreen forests on limestone soil of Xuan Lien National Park. It was collected in flower in April. Plants observed growing in the vicinity include Piper acreanum C.DC., Beccarinda tonkinensis (Pellegr.) B.L.Burtt, Sarcosperma kachinense (King & Prain) Exell, Hoya vercillata (Vahl) G.Don, and Alangium salviifolium (L.f.) Wangerin.

Conservation status.

Jasminanthes xuanlienensis is known only from the type locality, an area still poorly known botanically; its preliminary conservation status is therefore Data Deficient (DD; IUCN 2014).

Notes.

The six species of Jasminanthes are clearly distinguishable from one another based on morphological characters (Table 1 ). The new species can be easily separated from all Jasminanthes species as it has very long peduncles (14-18 cm long), while the longest peduncles observed in other species are those of Jasminanthes pilosa (Kerr) W.D.Stevens & P.T.Li and Jasminanthes saxatilis (Tsiang & P.T.Li) W.D.Stevens & P.T.Li), which reach 4 cm long. Jasminanthes xuanlienensis has unique pink corolla lobes whereas the other species have white corollas, or greenish corollas in Jasminanthes saxatilis .

Figures

Figure 1. Jasminanthes xuanlienensis T. B. Tran & Rodda. A Flowering branch in the habitat of the type locality (22 April 2013) B Inflorescence C Flower, top view D Pollinarium E Gynostegium and staminal corona. aa: anther appendage; ca: caudicle; cl: corona lobe; co: corpusculum; gr: guide rail; p: pollinium; sh: style head. (Photographs by T. B. Tran, photo edit by M. Rodda)