Agapetes lichengii Y. H. Tong & B. M. Wang sp. nov.

Figs 1, 2

Type.

China. Xizang Autonomous Region • Mêdog County, Beibeng Xiang, Deyanggou, ca. 680 m a. s. l.; 15 January 2024; Jing-Bo Ni, Bing-Mou Wang & Cheng Li TYH-2813 (holotype IBSC, isotypes IBSC, PE).

Diagnosis.

Agapetes lichengii is morphologically similar to A. pentastigma in having pseudo-whorled leaves, corymbose inflorescences, greenish yellow corolla with crimson transverse bands and capitate stigmas, but can be distinguished from it by the elliptic to oblanceolate (vs. oblong-lanceolate) leaf blades with an obtuse or slightly auriculate (vs. attenuate) base, corolla with a constricted (vs. not constricted) basal part, V-shaped (vs. ladder-like) stripes and triangular and spreading or slightly reflexed (vs. triangular-lanceolate and reflexed) lobes, anthers without dorsal spurs (vs. with two small dorsal spurs), stigma without gap between crenae (vs. with obvious gap between crenae), and filament scars forming a rounded ring (vs. a pentagonal ring) on fruit top (Fig. 3; Table 1).

Description.

Evergreen shrubs, epiphytic, with woody fusiformed tubers. Branches robust, dark brown, glabrous. Leaves alternate, pseudo-whorled; petiole subsessile, 1–3 mm long, light green, glabrous; blades leathery, adaxially green, abaxially pale green, elliptic to oblanceolate, 13–22 × 4.2–7.5 cm, length: width 2.6–4.2, glabrous on both sides, midvein impressed at base, flat or slightly elevated on the upper half, raised abaxially, lateral veins 17–19 pairs, together with veinlets raised and conspicuous on both sides; leaf base obtuse or slightly auriculate, margin repand, subentire or obtusely dentate, each dentation with a gland at the tip, apex obtuse or acute. Inflorescence corymbose, 2–9 - flowered, axillary; rachis 2–9 mm long, glabrous; bracts small, lanceolate to linear, 2–4 mm long, margin ciliate, apex acute; bracteoles 2, inserted at the base of pedicel, lanceolate, glabrous, 1–2 mm long; pedicels expanded upwards, clavate, 2.6–3.5 cm long, glabrous, articulated with calyx. Calyx tube green, 4–5 mm long, glabrous, lobes narrowly triangular, 7–15 × ca. 4 mm, glabrous, apex acute. Corolla pale yellow to greenish yellow, cerise on angles, with crimson V-shaped transverse bands between angles, tubular, constricted at base, slightly wider in the middle part, 5 - angled; tube 4.5–5 × ca. 0.8 cm, glabrous on both sides; lobes yellowish green, triangular, 8–9 × 6–7 mm, apex acute, glabrous, spreading or slightly reflexed. Stamens 10, 4.5–4.7 cm long, filaments flat, curved, 5–6 mm long, pubescent on the upper part; anthers coherent, 4.1–4.4 cm long, thecae densely echinate, brown, 6–7 mm long, tubules 3.5–3.7 cm long, sparsely echinate, opening by apical pores, without spurs on the back. Ovary inferior, pseudo- 10 - locular, each locule with several ovules; disc yellowish, glabrous; style slender, ca. 5 cm long, glabrous, slightly expanded upwards, exserted ca. 6 mm from the connate anther tubules; stigma capitate, 5 - crenated, without obvious gap between crenae. Infructescence rachis 1.9–2 cm long, ca. 4 mm thick, glabrous. Fruit pedicel greenish white, 2.8–3 cm long, expanded upwards, ca. 6 mm thick at top. Young fruits greenish, cup-shaped, 1.5–1.7 cm long including persistent calyx lobes, 0.8–0.9 cm in diam., flat topped with a rounded ring of 10 distinct filament scars.

Etymology.

The species is named in honor of Mr. Li Cheng, who devoted lots of time and energy to the biodiversity conservation of Mêdog County, and is also one of the discoverers of this new species. The Chinese name is given as 李成树萝卜 (pinyin: lĬ chéng shù luó bo).

Phenology.

Flowering from October to November; fruiting in March.

Distribution and habitat.

At present, Agapetes lichengii is known only from the type locality, i. e., Mêdog County, Xizang Autonomous Region, China. It usually grows on large tree trunks near the crown in rainforests at an elevation of ca. 680 m.

Additional specimen examined.

Agapetes lichengii: China. Xizang Autonomous Region • Medog County, Beibeng Xiang, Deyanggou, ca. 680 m a. s. l., cultivated in a greenhouse in Guangzhou; 5 June 2025; Bing-Mou Wang s. n. (paratype IBSC).

Agapetes pentastigma: Myanmar. Kachin State • Along the Ledo Road, between Namyung and Shinbweyan, 5–7 miles from Shinbweyan toward Namyung, in border area of Sagaing Region, Hukaung Valley Tiger Reserve, 26°42'32"N, 96°11'55"–13'01"E, cultivated in the Setsunan University; 11 November 2014, Hiroko Murata & Jin Murata 1402 (holotype TI, not seen; isotypes NY, image!, RAF, not seen, TNS, image!).

Taxonomic notes.

According to Airy Shaw’s infrageneric classification (Airy Shaw 1935, 1948, 1958), A. lichengii should be assigned to Agapetes subser. Coriaceae Airy Shaw due to its large leathery leaf blades with a repand margin, corymbose inflorescence and large flowers. Agapetes lichengii is morphologically mostly similar to A. pentastigma, but these two species are different in the morphology of leaves, corolla, anthers, stigma and fruit. Detailed morphological comparison is presented in the diagnosis part. It should be noted that some characters may change during different development stages, such as the shape of stripes on corolla tube, the bend degree of corolla lobes or the shape of stamen scar, so we made the comparison by using materials nearly at the same stage, such as fully open flowers or mature fruits, and we found that these characters are very useful to distinguish these two species. As for the differences in corolla tube shape and stigma morphology, they are actually consistent and irrelevant to the development stage. Besides, the two species are allopatric: A. lichengii is only found in Mêdog County, while A. pentastigma is endemic to Kachin State of Myanmar.

There are two kinds of stigma in Agapetes species: (1) small, truncate (or punctate) and inconspicuous; (2) capitate and conspicuous (Airy Shaw 1935, 1948, 1958; Fang and Stevens 2005; Murata and Murata 2020). While the ‘ small’ stigma is prevalent across a large portion of the genus, only a few taxa (e. g., A. affinis (Griff.) Airy Shaw, A. bhareliana (Airy Shaw) D. Banik & Sanjappa, A. hillii Brandis, A. loranthiflora D. Don ex G. Don (fide Watthana 2015), A. marginata Dunn, A. odontocera (Wight) Hook. f., A. pentastigma, A. salicifolia C. B. Clarke, A. setigera D. Don ex G. Don, A. sikkimensis Airy Shaw, A. variegata D. Don ex G. Don, and the present new species), possess the ‘ capitate’ stigma (Banik and Sanjappa 2014; Murata and Murata 2020). Consequently, stigma morphology is seldom used for species delimitation. The two similar Agapetes species (i. e. A. lichengii and A. pentastigma) presented here both have ‘ capitate’ stigma, but the detailed ornamentations on the stigma surface are very different (Fig. 3 C). And this distinguishing character is so stable and consistent that we believe that it could be served as a useful character for identification of Agapetes species. But this character seems to be only available for living material, and the stigma surface ornamentation would become barely seen when dried due to the shrinkage. As most descriptions of stigma in Agapetes are oversimplified, and some taxa even lack descriptions of their stigmas, we suggest that researchers pay more attention to the stigma surface ornamentation of Agapetes species in the future, which might offer us better understanding of the species of this genus.