Vaccinium motuoense Y.H. Tong & Y.J. Guo, 2021

Tong, Yi-Hua, Zhao, Wang-Lin, Wang, Bing-Mou, Liu, En-De, Cai, Jie & Guo, Yong-Jie, 2021, Vaccinium motuoense (Ericaceae), a new species from Xizang, China, PhytoKeys 181, pp. 105-111 : 105

Vaccinium motuoense Y.H. Tong & Y.J. Guo sp. nov.

Figures 1 , 2

Type.

China. Xizang Autonomous Region: Motuo County, Km 80 on Zhamo Road , epiphytic on trees in evergreen broad-leaved forest, 29°40'59.9"N, 95°30'6.3"E, 2191 m a.s.l., 28 May 2021 (fl.), Z. Liu & W. L. Zhao TYH-2523 (holotype: IBSC, isotypes: IBSC, KUN) .

Diagnosis.

Similar to V. dunalianum Wight, especially V. dunalianum var. urophyllum Rehder & E. H. Wilson, in the hairy young branches, the shape, size and indumentum of leaf blade and the axillary racemose inflorescence, but distinguished by the yellowish-brown tomentose (vs. glabrous or brownish-white pubescent) young branches, petioles and inflorescence rachis, leaf blades with 2-3(-4) pairs (vs. 4-5) of secondary veins, usually all basal (vs. only lowermost 2-3 pairs basal), with veins impressed adaxially (vs. plane or slightly raised) and flowers with urceolate to spherical corollas (vs. broadly campanulate) (Table 1 ).

Description.

Evergreen shrubs, epiphytic on tree trunks, sprawling or hanging, stem 0.5-3 m long, without swollen basal tuber or root swellings. Young branches brownish, slightly angled, without lenticels, yellowish-brown tomentose, glabrescent and becoming greyish-white when older. Perennating buds dimorphic (floral perennating buds are at least twice the size of vegetative perennating buds). Leaves alternate; petiole flattened above, 0.8-1.2 cm long, 1.7-2.2 mm wide, yellowish-brown tomentose throughout, glabrescent; blade ovate or ovate-elliptic, 8.5-13.5 (including caudate apex) × 2.4-5.0 cm, leathery, abaxially with dense appressed black-glandular trichomes, brown-tomentose or -pubescent on veins that are near leaf base both sides, otherwise glabrous, base broadly cuneate to rounded, with one basal gland per side at the junction of leaf base and petiole, margin flat or slightly revolute when dry, entire, apex long caudate 2-4 cm long; veins impressed adaxially, more so when dry, raised abaxially, secondary veins 2-3(-4) per side, usually all basal, short cross-veins (tertiary veins) between the secondaries prominent, nearly transverse and paralleled. Inflorescence racemose, usually axillary on biennial branches, 7-16-flowered. Peduncle usually very short, inflorescence rachis pale green, 0.7-3 cm long, yellowish-brown tomentose, glabrescent when fruiting; bracts pale green, obovate, cucullate, 6-8 × 4-6 mm, abaxially yellowish-brown tomentose or pubescent, adaxially glabrous, margin ciliate, caducous; bracteoles 2, inserted at base of pedicel, pale green, linear, 5-6 × ca. 0.2 mm, ciliate, caducous. Pedicel pale green, 2.5-4.5 mm long, yellowish-brown tomentose or pubescent or nearly glabrous, articulate with the hypanthium. Hypanthium green, cupuliform, 1.5-2.0 × 1.2-1.5 mm, glabrous; calyx limb lobed nearly to base, lobes 5, green, triangular, ca. 1.5 × 1 mm, apex acuminate, margin ciliate, with denser and longer cilia at apex. Corolla white or virescent, sometimes tinged with red on angles when young, urceolate to spherical, slightly angled when young, 4.5-6 × ca. 4.5 mm, glabrous outside, pubescent inside, 5-lobed; lobes ovate-triangular, reflexed, ca. 1 × 1.2 mm. Stamens 10, 4-4.5 mm long; filaments flat, slightly S-shaped, 1.5-2.0 mm long, puberulous and pubescent adaxially, slightly puberulous abaxially; anthers 3.0-3.5 mm long, thecae 1.5-1.7 mm long, tubules narrower than the thecae, 1.5-1.8 mm long, each with an oblique pore 0.7-1.0 mm long, 0.2-0.3 mm in diam.; spurs 2, borne at abaxial base of tubules, 0.8-1 mm long, echinate. Disc yellowish, annular, glabrous; style cylindrical, slightly angled in sicco, 5.0-5.2 mm long, glabrous, stigma punctate; ovary pseudo-10-locular, each locule with 8-10 ovules. Fruiting pedicel 4-11 mm long, expanded at apex; berry green when young, turning dark red later and finally dark purple at maturity, globose, 4-6.5 mm in diam., glabrous, with persistent calyx lobes appressed at apex. Seeds ovoid, 1.2-1.5 × 0.8-1 mm, testa brownish, reticulate, soft.

Etymology.

The species epithet is named after the type locality, Motuo County.

Vernacular name.

墨脱越橘 (Chinese pinyin: mò tuō yuè jú).

Distribution and habitat.

This species is currently known only from Motuo County, Xizang, China. It grows on trees in evergreen broad-leaved forests at elevations of 1600-2300 m.

Conservation status.

Vaccinium motuoense is common in the forests of Motuo County within an area over 3000 km2 and the whole area is under the protection of Yarlung Zangbo Grand Canyon National Nature Reserve. The threat risk seems to be low because it is not economically valuable and the conservation condition of the Reserve is good. Thus, it is assigned a status of 'Least Concern’ (LC), following the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2019).

Phenology.

Flowering in April-May and fruiting in October-March.

Additional specimens examined (paratypes).

China. Xizang, Autonomous Region, Motuo County: 3.5 km away from Bolonggong to Km 52 on Zhamo Road, 31 May 2013 (fl.), J. Cai, E. D. Liu & Y. J. Guo 13CS7683 (KUN); Km 80 on Zhamo Road, 5 January 2020 (fr.), Y. H. Tong & B. M. Wang TYH-2381 (IBSC); ibid. 12 January 1983 (fr.), B. S. Li & S. Z. Cheng 02486 (KUN); Beibeng Xiang, Buqiong Hu, 11 November 1992 (fr.), H. Sun, Z. K. Zhou & H. Y. Yu ETM-1145 (KUN); Beibeng Xiang, Gelin Cun, 20 May 1983 (fl.), B. S. Li, Z. C. Ni & S. Z. Cheng 03651 (KUN), 3 January 2020 (fr.); ibid. Y. H. Tong & B. M. Wang TYH-2338 (IBSC); Beibeng Xiang, Xirang, Sangxingpeng, 26 April 1983 (fl.), B. S. Li, Z. C. Ni & S. Z. Cheng 04317 (KUN); Beibeng Xiang, Xirang, Xideng Shan, 25 April 1983 (fl.), B. S. Li, Z. C. Ni & S. Z. Cheng 04752 (KUN); ibid. 12 January 1983 (fr.), B. S. Li, Z. C. Ni & S. Z. Cheng 02486 (KUN); Damu Xiang, 6 March 1993 (fr.), H. Sun, Z. K. Zhou & H. Y. Yu ETM-4243 (KUN); Damu Xiang, Dachi Shan, 30 October 1982 (fr.), B. S. Li & S. Z. Cheng 01600 (KUN, PE); Damu Xiang to Gedang Xiang, 13 March 1993 (fr.), H. Sun, Z. K. Zhou & H. Y. Yu ETM-4562 (KUN); Gedang Xiang, 21 March 1993 (fr.), H. Sun, Z. K. Zhou & H. Y. Yu ETM-4920 (KUN); without precise locality, without date, H. Sun, Z. K. Zhou & H. Y. Yu ETM-2621 (KUN).

Figures

Figure 1. Vaccinium motuoense sp. nov. A, B habit C sterile branch with leaves D inflorescence E fruiting branch F fruits, cross section A, C, E and F taken by Y. H. Tong B by W. L. Zhao and D by J. Cai.

Figure 2. Vaccinium motuoense sp. nov. A sterile branches with leaves B inflorescence C calyx D corolla E opened corolla, showing pubescent internal surface F stamens, adaxial, abaxial and lateral view G transection of fruit H infructescence (Drawn by Ding-Han Cui). Scale bars: 2 cm (A, B, H); 5 mm (C, G); 2 mm (D, E); 1 mm (F).