Hedyotis konhanungensis B.H.Quang, T.A.Le, K.S.Nguyen & Neupane, 2023

Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Linh, Le Thi Mai, Nguyen, Quoc Luan, Ngo, Duy Hoang Vu, Wu, Lei & Neupane, Suman, 2023, Hedyotis konhanungensis (Rubiaceae): A new species from the central highlands of Vietnam, PhytoKeys 221, pp. 73-84 : 73

Hedyotis konhanungensis B.H.Quang, T.A.Le, K.S.Nguyen & Neupane sp. nov.

Figs 2 , 3

Type.

Vietnam. Central Highlands of Vietnam, Kon Ha Nung Biosphere Reserve, Gia Lai province: K’Bang District, Kon Pne Commune , 14°20'53"N, 108°20'48"E, primary evergreen forest slopes at elevation 1150 m a.s.l., 28 November 2021, Nguyen Quoc Luan, Ngo Duy Hoang Vu & Le Tuan Anh LTA 531 (holotype: VNMN!; isotypes: HN!) .

Diagnosis.

Hedyotis konhanungensis is similar to H. shenzhenensis , H. shiuyingiae and H. yangchunensis from southeastern China (Guangdong and Hongkong) in the morphology of the leaf blades, floral bracts, dichasial cymes, and fruits, but differs from them by its broadly ovate or deltoid (vs. triangular or broadly triangular) stipules with entire (vs. hairy or lacerated) margins and cuspidate (vs. acute) apex, suborbicular or broadly oval (vs. subovate or ovate to lanceolate) lowest floral bracts, ovate or nearly oval (vs. triangular or subulate to lanceolate) persistent calyx lobes on fruits, and stamens in long-styled flowers inserted in lower ¼ or near the base (vs. at the middle or near the mouth) of the corolla tube (Table 1 ).

Description.

Perennial herbs, erect, 15-25 cm tall, completely glabrous. Stem simple, rarely branched, terete, 8-18 cm long, 5-7 mm in diam.; internodes 1-1.5 cm long. Leaves 5-7 pairs per stem, decussate, evenly spaced along the stem, abaxial side dark green, adaxial side glossy, dark purple to purplish black; petioles 4-6 mm long; blade flattened, thick, fleshy (subcoriaceous when dried), obovate-lanceolate to nearly oval, 6-10 × 2-4 cm; base decurrent or cuneate; apex broadly acute or obtuse; midrib depressed adaxially and prominent abaxially; 4-5 secondary veins on each side of the midrib, inconspicuous on adaxial side. Stipule interpetiolar, fused to leaf bases or very shortly around stem, broadly ovate or deltoid, 2.5-3 mm long, 5-6 mm wide at base, flattened, dark purple outside; apex cuspidate or aristate, with aristae 3-4 mm long and 0.7-0.9 mm wide; margins entire. Inflorescence terminal, a compound dichasial cyme, 5-7 cm long, with 3-4 orders of branching, purplish, 30-50-flowered. Peduncle terete, 2-4 cm long; bracts subtending the basal branches of the inflorescence leaf-like, suborbicular or broadly oval, slightly concave, 2-2.5 × 1.5-2 cm, with apex rounded to broadly acute or obtuse, abaxially dark purple to dark bluish purple, pale green adaxially; bracts subtending the upper inflorescence branches smaller, ovate or lanceolate, 0.8-1.5 × 0.5-1 cm, with acute apex. Pedicels terete, 3-6 mm long, usually bluish purple or purplish, bracteolate or ebracteolate; bracteoles narrowly ovate or lanceolate, somewhat concave, ca. 2.5 mm × 1.5 mm, with apex broadly acute or obtuse. Flowers 4-merous, distylous. Calyx hypanthium, bluish purple, cupular, 0.8-1.2 mm long and wide, glossy and glabrous; lobes 4, sub-equal, ovate or nearly oval, somewhat longitudinally concave, 1.7-2.2 mm long, 0.8-1.4 mm wide, broadly acute to obtuse at apex, adaxially white or purplish white, abaxially bluish purple. Corolla narrowly infundibuliform or tubular, bluish purple outside, white pubescent inside; tube 6-7 mm long, 1-1.5 mm wide, slightly enlarged at both ends; lobes 4, strongly reflexed, triangular-ovate, 1.5-1.8 × 1.2-1.5 mm, acute, adaxially white or purplish white, sparsely puberulent near base on adaxial surface. Longistylous flowers: stamens inserted in the lower ¼ of corolla tube, 1.5-2 mm above the base of tube; filaments very short, ca. 0.2 mm long; anthers linear, 1-1.2 × 0.2 mm, dorsifixed, introrse; style filiform, 5.5-6.5 mm long, white, glabrous, 2-parted; lobes oblong, 0.6-0.7 mm long, abaxially minutely papillose, pure white, slightly exserted beyond the corolla mouth; ovary inferior, 2-locular, with numerous ovules, placentation axile. Brevistylous flowers: stamens inserted on the upper ¼ of corolla tube, 1-1.5 mm below the corollas mouth; filaments and anthers similar to those in the long-styled flowers; style filiform, 1.5-1.8 mm long, 2-parted; lobes oblong, 0.6-0.7 mm long, densely papillose abaxially. Disks fleshy, ring-shaped, concave in the center, glabrous, white. Fruits capsular, nearly cupuliform with slightly concave top, 2.5-3 mm in diam., glabrous, purplish, crowned by the persistent, unveined, oval or nearly oval calyx lobes. Seeds many, black, irregularly angular, reticulate, minute, 0.3-0.5 mm long.

Additional specimens examined

(Paratypes). Vietnam. Central Highlands of Vietnam. Kon Ha Nung Biosphere Reserve, Central Highlands of Vietnam, Gia Lai province: K’Bang District, Kon Pne Commune, 14°20'43.06"N, 108°20'38.33"E, 906 m a.s.l., 26 March 2022, Bui Hong Quang et al. BHQ 453 (HN, and herbarium of Kon Ka Kinh National Park ) .

Etymology.

This species is named after the "Kon Ha Nung Biosphere Reserve" where it was discovered.

Vernacular name.

Vietnamese: An đi ền Kon Hà Nừng

Phenology.

Flowering in October to November, fruiting from November to December.

Distribution and ecology.

Hedyotis konhanungensis is recorded only from the type locality in the Kon Pne Commune of the Central Highlands of Vietnam, which is part of the Annamite Range. This range is known for its rich biodiversity and high number of endemic species ( Averyanov et al. 2003). The species grows in the understorey of the evergreen forests in the valleys or on flat areas to slopes of sandstone mountains. Within its occupancy areas, the new species was associated with some shrubs or herbs such as Pavetta bauchei Bremek., Lasianthus biflorus (Blume) M.Gangop. & Chakrab., Staurogyne sp., Popowia sp., Huperzia sp.

Figures

Figure 2. Hedyotis konhanungensis A habitat B habit C stipule D adaxial and abaxial leaf surfaces E inflorescences top view F long-styled and short-styled flower G infructescence H fruiting branch. Photos by Q. L. Nguyen and B. H. Photos by Quang, from Luan et al. LTA 531.

Figure 3. Hedyotis konhanungensis A habit B stipule C inflorescence D floral bracts E bracteoles and fruits F, G calyx top and side views H-K long-styled flower, entire and open showing pistil, corolla and anthers L-P short-styled flower, dissection showing calyx, corolla, anthers and pistil Q-T fruit, entire and dissection U seeds. Photos and design by B. H. Quang from Luan et al. LTA 531.