Hoya pyrifolia E.F. Huang, 2021

Huang, Er-Feng, Yao, Gang, Jiang, Ri-Hong, Yang, Lei-Lei, Xi, Wang, Zhang, Zhong-Shuai & Zhang, Xian-Chun, 2021, Hoya pyrifolia (Apocynaceae), a new species from south-western Yunnan, China, PhytoKeys 174, pp. 95-106 : 95

Hoya pyrifolia E.F. Huang sp. nov. Figures 3 , 4

Diagnosis.

The species is morphologically most similar to H. engleriana , but differs by its leaves which are pyriform and 10-14 mm long (vs. narrowly oblong and 20-25 mm long), its 4-flowered inflorescences (vs. 5-7-flowered), its calyx lobes ca. 4 mm long (vs. 1.5-2 mm long) and the triangular corolla (vs. narrowly oblong to oblong-triangular).

Type.

CHINA. Yunnan Province, Yingjiang Hsien, Sudian Village, Mulonghe River , epiphytic on trunk in mid-montane evergreen forest, 25°9'38"N, 97°53'20"N, at an elevation of 1865 m, 13 August 2019, E. F . Huang 1905009 (Holotype: PE!; isotypes: PE!) .

Description.

Epiphytic shrubs. Stems up to 60 cm in length, 3-4 mm in diam., branching mainly near base, branches pubescent, internodes shorter than leaves. Leaves opposite, pyriform, 10-14 × 4-7 mm, fleshy, slightly pubescent and dark green adaxially, glabrous and greyish-green abaxially, base obtuse or rounded, apex rounded or truncate, margin entire and reflexed; mid-vein invisible adaxially, obscure abaxially, lateral veins invisible on both surfaces; petioles ca. 2 mm long. Inflorescences terminal pseudumbels, flat-topped, 4-flowered, pendent; peduncle shorter than pedicels, 8-10 mm long, light green; bracteoles 2 at each pedicel base, linear, 4 × 1 mm; pedicels 1.3-1.5 cm long, light pink to yellow-green, pubescent; calyx lobes pinkish, narrowly triangular to linear, 4 × 1 mm, margin entire; corolla white, flat to slightly incurved, 1.5-1.7 cm in diam., lobes triangular-ovate, ca. 7 mm wide, apex acute; corona rose-coloured, ca. 6 mm in diam., ca. 3 × 3 mm, scales 5, fleshy, translucent, ovate-triangular; pollinia oblong, ca. 0.6 × 0.2 mm, base and apex truncate, caudicula attached at the centre of the retinaculum. Ovaries 2, attached to each other below centre, free higher up, oblong, ca. 2 mm long, ca. 1 mm wide, yellowish-white, pubescent. Follicles linear, 10-12 cm long, pubescent. Seeds linear-oblong, ca. 2.0 × 0.2 mm, coma 2.8-3.0 cm.

Distribution and habitat.

The species is endemic to Gaoligong Mountain, distributed in Longling and Yingjiang Counties in Yunnan Province. It is an epiphyte on tree trunks in the mid-montane evergreen forests at an elevation from 1850 m to 2150 m.

Etymology.

Hoya pyrifolia is named for its pyriform leaf, which is a significant feature that can be used to distinguish the species from its close relatives.

Other specimen examined.

CHINA. Yunnan Province, Longling Hsien, Gaoligongshan National Forest Park, 4°50'3"N, 98°45'48"E, at an elevation of 2146 m, 26 August 2019, E. F. Huang 201908260012 ( IBSC) .

Figures

Figure 3. Hoya pyrifolia E. F. Huang A habit B leaf C inflorescence D bracteole E calyx lobes F corolla, adaxial side G corolla, abaxial side H corona I corona lobe J pollinarium K fruit L seed. Drawn by Y. J. Chen.

Figure 4. Hoya pyrifolia E. F. Huang A habit showing inflorescences and mature follicles B branch and inflorescence C corona lobes D corona top view E flower F bracteoles G pollinarium H pedicel and calyx lobes I part of Pedicel J corona side view K leaves L seed.