Agapetes xiana Y.H.Tong, 2016

Tong, Yi Hua, 2016, Agapetes xiana sp. nov. (Ericaceae) from Xizang, China, Phytotaxa 252 (4), pp. 289-292 : 289-291

Agapetes xiana Y.H.Tong , sp. nov. ( Figs 1 & 2 )

This new species is similar to A. xizangensis Huang (1987: 315) and A. subansirica Pal & Thothathri (1984: 239) , but differs from the former by its larger leaves, longer pedicels, smaller calyx lobes, yellowish green corollas and longer stamens, and it can be distinguished from the latter by having inflorescences with fewer flowers, much longer pedicels, corollas and stamens.

Type:— CHINA. Xizang: Mêdog, Xirang to Deyang , epiphytic on trees on river banks, 1500 m, 21 Apr. 1983, B. S. Li & S. Z. Cheng 4213 (holotype PE!; isotype KUN) .

Shrub epiphytic, 2–3 m tall. Twigs slightly angled, lenticellate. Leaves scattered; petiole 1–1.5 cm long, glabrous, channeled; blades oblong-lanceolate, 22–30 × 6–10 cm, leathery, glabrous, midvein and lateral veins impressed adaxially, raised abaxially, secondary veins 6–8 pairs, anastomosous beneath the leaf margin, base rounded to shallowly cordate, margin entire, apex acute to acuminate. Inflorescences corymbose, axillary, ca. 6-flowered; peduncle ca. 3 cm long, slightly expanded upwards, glabrous; bracts caducous, not seen; pedicles 3.5–4.2 cm long, expanded upwards, cup-shaped apically, ca. 3 mm wide, glabrous. Calyx tube campanulate, ca. 7 mm long, glabrous, 5-angled; lobes triangular, ca. 3 × 2 mm, apex acute, with 1 midvein and 1–2 lateral veins, glabrous. Corolla yellowish green, with several brown transverse zigzag bands, tubular, 2–2.2 × 0.6–0.8 cm, glabrous; lobes triangular, ca. 2 × 2 mm, acute at apex. Stamens 10, ca. 1.9 cm long; filaments ca. 3 mm long, glabrous, slightly curved; thecae ca. 3 mm long, papillate; tubules ca. 1.3 cm long, without spurs abaxially. Style glabrous, ca. 2.2 cm long; stigma capitate. Fruit not seen.

Distribution and habitat:— This new species is known only from the type locality, Mêdog County, Xizang Province, China. It grows on trees on riverbanks in rainforest at an elevation of 1500 m.

Etymology:— This species is named after the author’s PhD student teacher Xia Nian-he, who gave the author careful guidance during the taxonomic research on Agapetes .

Paratype:— CHINA. Xizang: ibidem, 21 Apr. 1983, B. S. Li & S. Z. Cheng 4212 (PE!).

Notes:— This species is similar to Agapetes xizangensis and A. subansirica , particularly in the large leathery leaves and long peduncled corymbose inflorescence, but differs from the former by its larger leaves (22–30 × 6–10 cm vs. 10–21 × 2–4.5 cm), smaller calyx lobes (2 × 2 mm vs. 6 × 4 mm), longer corollas (ca. 2.2 cm vs. ca. 1.7 cm) and longer stamens (ca. 1.9 cm vs. ca. 1.4 cm), and can be distinguished from the latter by having inflorescences with fewer flowers (ca. 6 vs. 16–25), longer pedicels (3.5–4.2 cm vs. 1–2 cm), much longer corollas (ca. 2.2 cm vs. ca. 0.8 cm) and longer stamens (ca. 1.9 cm vs. ca. 0.8 cm). The differences among the three species are summarized in Table 1 as follows. Agapetes xiana , just the same as its two affinities, i.e. A. xizangensis and A. subansirica , is assigned to Agapetes sect. Agapetes ser. Graciles Airy Shaw (1935: 25) subser. Longifoliae Airy Shaw (1959: 490) , which is characterized by oblong-lanceolate leaves, peduncled corymbose inflorescences, filaments shorter than anthers and ecalcarate anthers.

Figures

FIGURE 2. Agapetes xiana. (A) Flowering branch; (B) Calyx and style; (C) Opened corolla, abaxial view; (D) Stamen, adaxial and lateral view. From B. S. Li & S. Z. Cheng 4213 (PE).