Hedychium putaoense Y.H.Tan & H.B.Ding, 2018

Ding, Hong-Bo, Yang, Bin, Zhou, Shi-Shun, Li, Ren, Maw, Mya Bhone, Kyaw, Win Maung & Tan, Yun-Hong, 2018, Hedychium putaoense (Zingiberaceae), a new species from Putao, Kachin State, Northern Myanmar, PhytoKeys 94, pp. 51-57 : 52-55

Hedychium putaoense Y.H.Tan & H.B.Ding sp. nov. Figure 1

Diagnosis.

Hedychium putaoense Y.H. Tan & H.B. Ding is morphologically similar to H. densiflorum Wall. and H. longipedunculatum A.R.K. Sastry & D.M. Verma, but it can be easily distinguished by its very small bract (4-6 × 2.5-3 mm vs. 18-19 × 5-5.5 mm and ca. 11 × 7 mm, respectively) and bracteole (2-2.5 × 3-3.5 mm vs. ca. 9 × 2 mm and ca. 6 × 4 mm, respectively), orange flower and broadly falcate to lanceolate lateral staminodes.

Type.

MYANMAR. Kachin State: Putao District, the top of the mountain from Masabu village to Namti village . Epiphytic herbs in tropical montane forests, 97°17'42"E, 27°25'29"N. 1700 m a.s.l., 13 May 2017, flowering, Myanmar Exped. M 1724 (holotype: HITBC!; isotypes: HITBC!)

Description.

Epiphytic, sometimes terrestrial, perennial rhizomatous herbs, light greyish-green externally. Leafy shoot 20-50 cm high, slanting with erect inflorescence. Leaves 4, spreading, sessile, upper petioled; petiole 2-10 mm long; ligule ca. 8-19 mm long, apex obtuse, glabrous, membranous, translucent, reddish brown when fresh, yellowish brown when dry, closely appressed to the stem; lamina 13-23 × 3-7 cm, lanceolate, dark green above, pale green below, or sometimes light purple-tinged below, glabrous; margin undulate, membranous, non-ciliate; apex narrowly caudate, twisted, base attenuate. Inflorescences 7-10 cm long, cylindrical, dense, erect, rachis glabrescent. Bracts 4-6 × 2.5-3.0 mm, ovate, purplish-red, glabrous, convolute, margin ciliate, membranous, tip acute, cincinnus 1-flowered. Bracteoles 2.0-2.5 × 3.0-3.5 mm, semicircular, dark red, glabrous, membranous, acute at tip, margin ciliate. Flower 2.8-3.9 cm long, small, orange, nearly entire inflorescence open at a time, ascending. Calyx 1.2-1.4 cm long, 2.0-2.5 mm wide at mouth, tubular, pale light red, densely villous, tufted hairs at tip, membranous, upper half inflated, lower part closely appressed to corolla tube, unilaterally split up to ca. 5 mm depth. Corolla tube 10-13 mm long, creamy yellow, glabrous, tube intensely curved towards tip about 90° to 180°. Corolla lobes 10-16 × 1-2 mm linear-lanceolate, red, membranous, glabrous. Lateral staminodes 11-13 × 3-4 mm, broadly falcate to lanceolate, clawed towards base, orange, spreading on flower, obtuse at tip, intensely reflexed back. Labellum 12-14 × 4-7 mm, widely obovate, orange, spreading on flower, base cuneate, sinus ca. 2-3 mm deep, lobes oblong, obtuse at tip. Stamen 1.4-1.7 cm long. Filament 1.1-1.2 cm long, ca. 2 mm wide at base, orange, creamy yellow towards base, intensely curved towards tip about 180°. Anthers ca. 5 × 2 mm, oblong, orange, split opens from top to bottom, attached with the filament at ca. 1 mm above from base, thecae parallel with the filament; connective red, glabrous, non-crested. Ovary ca. 2.5 mm diameter, sub-globose, densely villous. Style filiform, creamy white, glabrous, dark red-tinged towards stigma. Stigma ca. 0.5 mm wide, dark red, cup-shaped, mouth margin ciliate, ca. 1 mm exserted from the anther. Epigynous glands 2, ca. 1 mm long, oblong, orange. Fruit unknown.

Phenology.

Flowering from May to July.

Distribution and habitat.

This new species is known to grow at the top of the mountain from Masabu village to Namti village, Putao District, Kachin State, where it grows epiphytically on the trees of tropical montane forests at an elevation of ca. 1400-1800 m.

Etymology.

The species is named after the type locality, Putao county, in Kachin State, Myanmar.

Affinities.

Hedychium putaoense Y.H. Tan & H.B. Ding shares certain characteristics with H. densiflorum ( Wallich 1832) and H. longipedunculatum (Sastry and Verma 1968), e.g. non-imbricating bracts, cincinnus 1-flowered, small and dense flower, oblong anther and sub-globose ovary. After comparison with specimens and descriptions in literature, it was found that H. putaoense can be clearly differentiated from the latter two species, even on the basis of their vegetative characters: e.g. the proportion of the bract to the calyx; H. putaoense has very small bracts that are shorter than the calyx (4-6 vs. 12-14 mm), whereas, the bracts of H. densiflorum are longer than the calyx (18-19 vs. 13-14 mm) and the bracts of H. longipedunculatum are equal in length with that of the calyx (ca. 11 vs. 11 mm). H. putaoense , furthermore, differs in having semicircular and dark red bracteole, corolla tube curved towards the tip by about 90° to 180°, orange lateral staminodes and labellum, filament intensely curved towards the tip by about 180°, densely villous ovary and dark red stigma. H. densiflorum has tubular and pale green bracteole, corolla tube slightly bent to one side towards the tip, orange-red lateral staminodes and labellum, straight filament, glabrous ovary and yellow stigma. H. longipedunculatum from India has notched ligule, hairy rachis, triangular bract, ovate bracteole, creamy yellow flower, erect corolla tube, straight filament and green stigma. A detailed comparison of the morphological differences amongst these taxa is given in Table 1 and the evidence from morphological analysis supports the recognition of H. putaoense as a distinct species.

Figures

Figure 1. Hedychium putaoense Y. H. Tan & H. B. Ding. a-b Habit c-d Inflorescence e-f Front and lateral view of flower g Bract h Bracteole i Calyx j-k Corolla lobe l-m Lateral staminodes n Labellum o Corolla tube with anther and calyx p Ovary with pistil and glands. Photographed by Y. H. Tan & H. B. Ding.