Diospyros xylocarpa Y. M. Shui, W. H. Chen & Sima, 2021

Sima, Yong-Kang, Chen, Wen-Hong, Wu, Jian-Yong & Shui, Yu-Min, 2021, Diospyros xylocarpa, a New Species of Ebenaceae from China and Vietnam, Phytotaxa 528 (2), pp. 133-138 : 133-136

Diospyros xylocarpa Y. M. Shui, W. H. Chen & Sima , sp. nov. ( Figs. 1–2 )

Type:— CHINA. Yunnan: Maguan, Gulinqing , Xiangyu Travel Station beside Mage River , 22°42’48” N, 103°58’02” E, elevation 500 m, in the tropical rainy forest along the limestone valley, 6 October 2002, Y. M . Shui , W. H . Chen & J. S . Sheng 30539 (holotype: KUN; isotypes: PE, IBSC)

Diagnosis:—The new species is similar to Diospyros phuketensis , but differs in its bigger (8.1–32.4 × 4.9–14.4 cm vs. 14–22 × 3.5–6.5 cm) and densely ochre brown villous (vs. glabrous) leaves, 7–16 (vs. 7–10) pairs of lateral veins, shorter petioles (6–9 mm vs. 10–15 mm), 8-locular (vs. 8(–10)-locular) ovaries, xyloid (vs. succulent) fruits with nearly square (vs. saucer-shaped) fruiting calyx and much shorter (4–5 mm long vs. 15–20 mm long) fruiting peduncle and 8 (vs. 8–10) seeds. The new species is also similar to D. dasyphylla , but differs in its leaf blades with a cuneate to round (vs. rotundate to subcordate) base, 8 (vs. 16) stamens and bigger (5.1–6.8 cm vs. 0.9–1.6 cm in diam.) and xyloid (vs. succulent) fruits.

Trees, up to 8–17 m tall and 20 cm DBH. Twigs densely ochre brown spreading villous. Terminal buds terete, densely glossy yellowish brown villous. Leaves oblong or elliptic, 8.1–32.4 cm long, 4.9–14.4 cm wide, chartaceous, glabrous and densely villous along the midrib adaxially, densely ochre brown spreading villouse specially along midrib, lateral and reticulate veins abaxially, margin entire; apex acuminate to caudate; base cuneate to round; midrib, lateral and reticulate veins prominent abaxially, depressed adaxially; lateral veins 7–16 pairs; petioles 6–9 mm long, grooved on the adaxial side, densely ochre brown spreading villous. Bisexual flowers solitary, terminal on axillary brachyblasts, 4-merous; peduncle 2–3 mm long, densely ochre brown tomentose, with a phyllary densely ochre brown tomentose outside; pedicel absent, with a bract densely ochre brown tomentose outside; calyx lobes 4, broad-ovate, densely ochre brown tomentose outside, glabrous inside; corolla white, tubular-urceolate, 4(–5)-lobed, 6–7 mm in diam., tomentulose on the outside surface of the tubule and on both surfaces of the lobes; stamens 8, 2-lobed, densely puberulent along filaments; ovary ovoid, tomentose, 8-locular; styles 4. Fruits globose, xyloid, 5.1–6.8 cm in diam., densely ochre brown tomentose, 8-locular; fruiting calyx nearly square, 1.1–1.4 cm in diam., 4-lobed, densely ochre brown tomentose outside; fruiting pedicel absent, with a bract densely ochre brown tomentose outside; fruiting peduncle 4–5 mm long, densely ochre brown tomentose, with a phyllary densely ochre brown tomentose outside; fruiting brachyblast 2–4 mm long, 4–5 mm in diam., densely ochre brown villous, with 4 to 5 scales densely ochre brown tomentose outside. Seeds 8, triangular-ovoid, laterally compressed, 3.6–3.9 cm long, 2.3–2.7cm wide, 1.7–1.9 cm crass.

Phenology:— Flowering February to April, fruiting May to November.

Distribution and habitat: —This new species is currently known only from Maguan County, Yunnan Province, China and from Cuc Phuong National Park, Ninh Binh Province, Vietnam. It was found in the tropical rainy forests along the limestone valley at elevations of 100–900 m, mainly composed of Caryodaphnopsis tonkinensis ( Lecomte 1913: 106) Airy Shaw (1940: 74) , Pometia pinnata Forster & Forster (1776: 110) , Saraca dives Pierre (1898 : t. 384B), Silvianthus tonkinensis ( Gagnepain 1948: 33) Ridsdale (1978: 42) , Euonymus pittosporoides C. Y. Cheng ex Ma (1998: 232) , Streblus macrophyllus Blume (1856: 80) , Ilex perlata C. Chen & S. C. Huang ex Li (1985: 8) , Phrynium rheedei Suresh & Nicolson (1986: 355) , Pseuderanthemum crenulatum (Wallich ex Lindley 1825: t. 879) Radlkofer (1883: 286), Ophiorrhiza gracilis Kurz (1872: 311) , Gnetum montanum Markgraf (1930: 466) .

Etymology:— Referring to the xyloid fruits of this new species.

Additional specimens examined (paratypes):— CHINA. Yunnan: Maguan County, the same locality as above, April 2004 (fl.), Y. M . Shui et al. 46009 ( KUN) . VIETNAM. Ninh Binh: Cuc Phuong National Park , 20°21’04” N, 105°36’10” E, in primary forest on hillside in valley, 21 July 1999 (fr.), N. M . Cuong , H. L . Quyen & M. V . Xinh 277 ( CHI); ibid., 20°22’54” N, 105°34’13” E, elevation 200 m, in primary forest, 28 August 2000 (fr.), N. M . Cuong , D. T . Kien & M. V . Sinh 1069 ( CHI) .

Conservation status:— At present, two subpopulations of Diospyros xylocarpa with a total of less than 50 mature individuals have been found in China and Vietnam during our investigations. All individuals discovered occur within the reserves, where the habitats are in good condition. According to IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Subcommittee 2019), this new species should be regarded as critically endangered (CR).

Figures

FIGURE 1. Diospyros xylocarpa Y. M. Shui, W. H. Chen & Sima.A. Leafy twig. B. The abaxial surface of lower part of a leaf blade. C. Flower. D. Longitudinal section of corolla, showing stamens. E. Young fruit with 4-lobed calyx and bracts. F. Fruit with 4-lobed calyx. G. Longitudinal section of fruit. H. Cross section of fruit. I. Seed. J. Cross section of seed. Scale bars: A and F–J =3.0 cm, B = 3.5 cm, C–E = 5.0 mm. Drawn by Xi-Lin Wu.

FIGURE 2. Diospyros xylocarpa Y. M. Shui, W. H. Chen & Sima.A. Habit. B. Longitudinal section of fruit. C. Fruiting twigs. D. Flower. E. Styles. F. Longitudinal section of corolla, showing stamens. Photos by Yu-Min Shui.