Tigridiopalma longmenensis H.F. Wang, H.L. Cao & H.G. Ye, 2021

Wang, Hui-Feng, Wang, Zheng-Feng, Qin, Qiao-Mei, Cao, Hong-Lin & Guo, Xiao-Ming, 2021, Tigridiopalma longmenensis (Melastomataceae), a new species from Guangdong, China, Phytotaxa 500 (3), pp. 241-247 : 244-246

Tigridiopalma longmenensis H.F. Wang, H.L. Cao & H.G. Ye , sp. nov. ( Fig. 4 )

Type: — CHINA. Guangdong Province: Huizhou City , Longmen County, 23°39′ N, 114°3′ E, 150 m, 12 September 2020, H. F. Wang, H. L. Cao & H. G. Ye 20200912001 (holotype, IBSC, barcode number 0858304; isotypes, IBSC, barcode numbers 0858305 & 0858306) .

Diagnosis: — Tigridiopalma longmenensis is similar to T. magnifica in the herbaceous habit, the 5-merous flowers, dimorphic and unequal stamens, short stamens with the decurrent connective of anthers forming a short spur, and funnelform shaped capsules. However, the former differs from the latter by the inflorescences being polychasia (vs. scorpioid cymes), hypanthia with carinas on angles (vs. winged on angles), and the longer (antesepalous) stamens with a conspicuously white or pink spur (vs. without spurs) at the connective bases of anthers ( Table 2, Fig. 2 ).

Perennial herbs. Rhizomes usually woody. Stems erect, short, sparsely pubescent, 1–1.5 mm long. Leaves basal, with soft hairs when young, yellow puberulent when old; petiole terete, 4.4–18.4 cm long, succulent, sparsely pubescent, sulcate when old; blades membranous, narrowly cordate to ovate, 20.8–51.8× 13.6–44.9 cm, margin ciliate and irregular abruptly denticulate, adaxially glabrous, abaxially densely furfuraceous, purplish red, puberulous on veins, secondary veins 2–3 pairs, tertiary veins parallel. Inflorescences axillary, polychasium consisting of 2–5 scorpioid cymes; peduncle 9.4–32.7 cm long, sometimes furfuraceous at base, ribbed when dry; bracts 0.8–8.7× 0.5–4.3 cm, persistent. Pedicel 0.9–1.9 mm long, with carinas on angles, 0.2–0.5 mm wide, sometimes furfuraceous. Hypanthium funnelform to cup-shaped, 5-sided, apex truncate, carina 0.2–0.5 mm wide on angle. Calyx lobes 5, triangular to semiorbicular, 0.3–0.5 mm long. Petals 5, 1.1–1.6× 0.8–0.9 cm, adaxially dark red, abaxially with white lines, broadly obovate, almost rhomboid, apex truncate, oblique, and apiculate. Stamens 10, dimorphic and unequal; longer stamens 5, antesepalous, filaments 1.6–1.9 cm long, anthers 0.8–1.2 cm long, connective decurrent, forming a conspicuous spur abaxially, white or pink, ca. 1 mm long, and two ventral tubercles, yellow, ca. 1 mm long; smaller stamens 5, antepetalous, filaments 1.1–1.4 cm long, anthers 0.5–0.8 cm long, connective decurrent, forming a spur abaxially, ca. 1 mm long and two ventral tubercles, yellow, ca. 1 mm long. Ovary ovoid, 5-celled, apex with membranous crown; crown 5-lobed, with irregularly denticulate margin; style 0.9–1.2 cm long, magenta, terete, slightly curved. Capsule dehiscing into 5 valves from the apex, valves ca. 2–3 mm long, with irregularly denticulate margin. Hypanthium partially covering the capsule, funnel-shaped, 6.5–7.5× 9.1–10.2 mm, 5-sided, angles carinated. Seed numerous, brown, cuneate, 0.6–0.8× 0.3–0.5 mm.

Etymology: —The specific epithet is derived from the type locality, Longmen County of Guangdong Province, China.

Geographical distribution and habitat: — Tigridiopalma longmenensis is only known from Longmen County, Huizhou City , Guangdong Province, China ( Fig. 1 ). It often occurs on the rock crevices near streamside in forests at low elevations of 93–175 m.

IUCN conservation assessment: —One population with more than 2500 individuals has been found in Longmen. There is no any significant or plausible threat to the habitat and the plant up to now. It is therefore evaluated as Endangered (EN B1a) according to IUCN Red List Criteria ( IUCN 2019).

Phenology: —Flowering from August to October; fruiting from October to November.

Additional specimens examined (paratypes): — CHINA. Guangdong Province: Huizhou city, Longmen County, Youtian Forest Farm, 23°38′ N, 114°2′ E, elev. 115 m, 20 August 2020, H. F . Wang & H. F . Zhu 20200820001 ( IBSC); ibid., 24 October 2020, H. F . Wang & Z. H . Wu 20201024007 ( IBSC); ibid., 23°39′ N, 114°3′ E, elev. 151 m, 26 November 2020, H. F . Wang , H . Dong & W. G . Zhu 20201126001 ( IBSC) .

Figures

FIGURE 1. The allopatric geographical distribution of Tigridiopalma longmenensis (one population) and T. magnifica (11 populations).

FIGURE 2. Comparison of Tigridiopalma longmenensis (A, C, E, G) and T. magnifica (B, D, F, H). Inflorescences: A. A polychasium consisting of five scorpioid cymes, B. A scorpioid cyme. Stamens: C. Anther connective decurrent forming a conspicuously white or pink spur abaxially in long stamens (the two on the right), D. Abaxial spur of anthers absent in long stamens (the two the right). Hypanthia: E. Carinas on angles of hypanthia of flowers, F. Wings on angles of hypanthia of flowers, G. Carinas on angles of hypanthia of capsules, H. Wings on angles of hypanthia of capsules. Photos A, C, E, G, from Longmen County, Guangdong; photos B, D, F, H from Ehuangzhang Nature Reserve in Yangchun City, Guangdong; all taken by H.F. Wang.

FIGURE 4. Tigridiopalma longmenensis. A. Habitat, showing plants in wild. B. Plants, showing polychasium. C. Leave, adaxial side. D. Leave, abaxial side. E. Petiole. F. Detail of inflorescence, showing polychasium consisting of scorpioid cymes. G. Small and large bracts. H. Flowers, top view. I. Flower, side view. J. Young fruits, showing carinas on angles of hypanthia. All photos from the type locality, taken by H.F. Wang.