Barringtonia laxiflora Thammar., Pornp. & Chantar., 2017

Thammarong, Woranart, Chantaranothai, Pranom & Pornpongrungrueng, Pimwadee, 2017, Three new species of Barringtonia (Lecythidaceae) from Myanmar and Vietnam, Phytotaxa 309 (2), pp. 151-158 : 151-153

1. Barringtonia laxiflora Thammar., Pornp. & Chantar. sp. nov. ( Figs. 1 & 4 )

Type:— VIETNAM. Thua Thien Hue: Phu Loc, Bach Ma National Park, elev. 800–900 m, 26 April 2003, N. T. Hiep et al. HLF 1351 (holotype: HN!).

Barringtonia laxiflora resembles B. macrostachya (Jack 1821: 47) Kurz (1875: 66) and B. pauciflora in leaf characters. The species differs from B. macrostachya by its erect inflorescence and pedicellate flower, and differs from B. pauciflora by its ovate leaf blades, longer inflorescence and pedicellate flowers.

Tree 8–12 m high. Leaves with petioles 2–6 cm long, glabrous; lamina ovate, 15–35 × 6–13 cm, base cuneate, apex acute, margin entire, subcoriaceous, upper and lower surfaces glabrous; secondary veins 13–15 pairs. Inflorescences erect raceme, 20–23 cm long, terminal, sparsely flowered with up to 30 flowers; rachis 4–7 mm diam., glabrous; bracts not seen. Flowers pedicellate; pedicels 10–15 mm long; hypanthium funnel-shaped, 5–7 × 2–3 mm, 4-gonous, glabrous; sepals 4, ovate, 5–10 × 5–9 mm, apex rounded, open in bud; petals 4, oblong, 12–25 × 5–10 mm, white; stamens 3–4 cm long in 2–3 staminal whorls, inner whorl staminodia 1; staminal tube 3–5 mm long; anthers subcircular, ca. 1 × 1 mm; disc 3–4 mm diam., ca. 0.5 mm high; ovary 2–4-locular; ovules 2–4 per locule; style 3.5–4 cm long; stigma rounded, ca. 0.2 mm in diam. Fruits not seen.

Distribution:—Endemic to Vietnam, known only from type location. ( Fig. 4 ).

Ecology:—In broadleaved evergreen secondary closed mountain forest on steep shale or granite slopes along road, elev. 800–1150 m.

Phenology:—Flowering in April.

Etymology:—The specific epithet refers to the lax or sparse arrangements of flowers on the inflorescence.

Conservation status:—This species is endemic to Vietnam and known only from a single locality in Bach Ma National Park, Thua Thien Hue that has an area of about 220 km 2. Further collections are needed to allow complete evaluation of this species. A conservation status of Data Deficient ( DD, IUCN 2012) is here considered on the basis of the data above. This apparently rare new species is in need of further survey to adequately areas its conservation status.

Notes:—This species is distinguishable by its erect inflorescence and pedicellate flowers. It resembles B. macrostachya and B. pauciflora in leaf characters but differs from the former by its erect inflorescence and pedicellate flower whereas B. macrostachya has pendulous inflorescence and sessile flowers. The species differs considerably from the latter in its ovate leaf blades, inflorescence of 20–23 cm long and pedicellate flowers. In contrast, B. pauciflora has elliptic leaf blades, inflorescence of 5–7 cm long and sessile flowers. A comparison of morphological characters are shown in Table 1. From the herbarium label information, the flower of B. laxiflora is strongly sweet-fragrant.

Additional specimens examined:— VIETNAM. Thua Thien Hue: Phu Loc, Bach Ma National Park, Khe Su, elev. 1100–1150 m, 20 April 2003, N. T. Hiep et al. HLF 1189 ( HN).

Figures

FIGURE 1. Barringtonia laxiflora: A. branchlet with inflorescence; B. flower bud; C. flower in cross section; D. petal. Drawn from N.T. Hiep et al. HLF 1351 (HN) by Woranart Thammarong.

FIGURE 4. Distribution of Barringtonia laxiflora (z), B. parkinsonii (*) and B. tomentosa („).