Agapetes nana

Yang, Bin, Ding, Hong-Bo, Zhou, Shi-Shun, Maw, Mya Bhone, Maung, Kyaw Win & Tan, Yun-Hong, 2019, Taxonomic studies on Agapetes in Myanmar I: Agapetes reflexiloba, a new species from Kachin State, and notes on three rediscovered species including two new records for Myanmar, Phytotaxa 393 (2), pp. 105-118 : 112-116

Agapetes nana ( Griffith 1854a: 303, 1854b: t.505) Hook. f. in Benth. & Hook. f. Gen . Pl. 2(2), 571,187 6 (Figures

4–5)

Type: India: Assam, Naga hills, 16 Mar. 1837, W. Griffith 26 (Kew distributed, No. 3473, K 000729410!)

Taxonomic synonyms: Agapetes nana (Griff.) Hook. f. var. robusta Airy Shaw, Kew Bull. 13(3), 474, 1958, syn. nov. Type:— Myanmar. Sumpra Bum, 5 Mar. 1953, F. Kingdon Ward 22017 ( BM 000752865!)

Epiphytic shrubs up to ca. 1 m tall. Twigs terete, with inconspicuous pale grey lenticels, 0.8–1.0 cm in diam., glabrous, young branches with ovate-lanceolate leaf-shaped buds scales, 1.0–1.6 × 0.3–0.5 cm. Leaves spirally aggregated, pseudoverticillate; petioles short, 3–6 mm long, subglabrous; leaf blades coriaceous or leathery, ovate-elliptic, 9.5– 14.5 × 3.5–5 cm, apex acute to obtuse, base attenuate to obtuse, glabrous, margins entire or slightly crenulate with short glandular hairs, and slightly revolute, midvein raised abaxially, impressed adaxially, secondary veins inconspicuous, 8–12 pairs, margin veins connected to a line. Racemose 15–20-flowered, 6–10 cm long, axillary or on leafless branches; peduncle stout, subfleshy, with short glandular hairs, 3.7–6 cm long, pink; bracts small, inconspicuous; pedicels stout, fleshy, cylindrical, white to slightly light pink, 1.5–1.7 cm long, ca. 4 mm in diam., glabrous, with conspicuous linear ancilla (ca. 2 mm long) apically; bracteoles basal, small, scale-like, triangular, ca. 1 mm long. Calyx tubular, 8–10 mm long, glabrous; calyx tube cylindrical, slightly pale blue, 3–4 mm long, 2–3 mm in diam., limb divided to lower part of middle; lobes pink, lanceolate, 5–6 × 1–1.5 mm. Corolla narrowly campanulate, 1.2–1.5 cm long, glabrous, colour unknown; lobes narrowly lanceolate to linear, 8–10 × 1–1.5 mm, strongly reflexed at anthesis. Stamens 10, ca. 1.2 cm long; filaments flat, ca. 5 mm long, glabrous; anthers 8–9 mm long, thecae maroon, ca. 1.5 mm long, papillate, tubules brownish yellow, 6.5–7.5 mm long; with 2 spurs abaxially, spurs ca. 2 mm long; Style ca. 1.3 cm long. Fruit oblate, white to pinkish white, 6–7 mm in diam..

Phenology: Flowering in March to April and fruiting in May to June.

Distribution and habitat: India, Myanmar: Kachin state, where it is an epiphytic shrub that grows on the trees in montane broadleaved forests, at 700–1,200 m a.s.l. ( Figure 6 ).

Specimens examined: Myanmar. Kachin State: Putao, near Upper Shankhaung, 97º 15 ʹ 40.17 ʺ E, 27º 26 ʹ 25.14 ʺ N, alt. 600 m, 18 May 2017, Myanmar Exped. 1888 (HITBC, RAF). Ibid., 18 Dec. 2017, Myanmar Exped. 3779 (HITBC, RAF). Ibid., 17 June 2018, Myanmar Exped. 4611 (HITBC, RAF).

Notes: Agapetes nana was first collected from the Naga Hills, which is now known as Nagaland, in North East India in 1837, and described and illustrated as Ceratostema nanum by W. Griffith in 1854. 22 years later, J.D. Hooker transferred it to the genus Agapetes as A. nana . Thereafter, no more specimens of this species had been found until Frank Kingdon-Ward, a famous plant hunter in the earlier period of the 20th century carried out his expeditions in Kachin State, North Myanmar from 1952 to 1953 ( Kingdon-Ward, 1957). His collections were the second known specimens of this most distinct species, and differed from Griffith’s in their much larger leaves. They were then described as a new variety under Agapetes nana by Airy Shaw (1958). During a floristic inventory of North Myanmar, we collected an interesting species of Agapetes growing on a tree in 2017. After consulting literature and specimens at JSTOR, one of the specimens has been identified as Agapetes nana . This appears to be the only record of this species for 64 years.

The rediscovery of living plants gives researchers an opportunity to expand its taxonomic description. Agapetes nana is unique among Myanmar’s Agapetes because of its distinct palisade of gland-tipped hairs which form a sort of epicalyx ( Figs. 4–5 ) ( Airy Shaw 1958). This species resembles A. sikkimensis Airy Shaw (1935: 29) , A. affinis ( Griffith1848: 84, no.1218) Airy Shaw (1958: 473) and A. auriculata ( Griffith 1854a: 300, 1854b: pl.508) Hook. f. (in Benth. & Hook. f. 1876: 571) in its spirally aggregated leaves and ovate-elliptic leaf blades, also in its racemose inflorescence, but they can be distinguished from each other by their pedicels and corollas. The differences between these three species are shown in Table 3.

Specimens of Agapetes pseudo-griffithii examined. Myanmar. Nam Tamai valley, alt. 1,200 –1,500 m, 15 Jan.1931, F. Kingdon-Ward 9144 (holotype: BM000833574, isotype: A00014624). Kachin State: Putao district, Naungmung Township, buffer zone of Hkakaborazi National Park, around Tup Kwan rest house, 98º 9 ʹ 38.3 ʺ E, 27º 36 ʹ 28.5 ʺ N, alt. 1,817 m, 25 Oct 2015, Kate A. et al. 974 (NYBG02648636).

Figures

FIGURE 4. Agapetes nana. A. Habit; B–C. Fruiting branch; D. Infructescence; E–F. Fallen flowers. Photographed by H.B. Ding & B. Yang.

FIGURE 5. Agapetes nana. A. Fruiting branch; B. Flower; C. Calyx along with part of pedicel; D. Calyx dissection; E. Stamen; F. Part of an infructescence. Illustration by Zhengmeng Yang.

FIGURE 6. Distribution of Agapetes reflexiloba, A. bhareliana, A. linerifolia, A. nana and A. pseudo-griffithii in Myanmar based on our field investigation and some specimen records.