Diospyros penghuae, a new species of Ebenaceae from Danxiashan mountain in Guangdong, China

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(1. State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources∥ State Key Laboratory for Biocontrol and Institute of Entomology∥School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China; 2. Administrative Commission of Danxiashan National Park, Shaoguan 512300, China)

Abstract：Diospyros penghuae, a new species of Ebenaceae endemic in Danxiashan mountain, Guangdong, China, is here described and illustrated. Morphologically, the new species is most similar to D. cathayensis and D. rhombifolia, but it differs in its evergreen shrub or small tree, non-spiny branchlets. The leaf shape and seed size are also clearly distinguished from D. cathayensis and D. rhombifolia. This new species is in honor of Prof. Peng Hua, School of Geography and Planning, Sun Yat-sen University, who made a significant contribution to our knowledge of Danxia Landform research.

Key words：Diospyros penghuae; Ebenaceae; new species; Guangdong province; Danxiashan mountain

DiospyrosLinnaeus is the largest genus of the family Ebenaceae. It consists of over 500 species and widely distributed in the tropics and subtropics[1]. The genusDiospyroshas a very complex biogeographical history and phylogenetic relationship, and its infrageneric classification is still not clearly resolved[2-3].Diospyrosis the only genus of Ebenaceae distributed in China with about 62 species (44 endemic). Among them,DiospyrosbrandisianaKurzis a new record species of China found in Yunnan, andD.leeiLiu Y., Shi S. & Huang Y. S. is a new species described from Guangxi[4-6]. In Guangdong province, 12 species were recorded in this genus[4], one of which,D.saxicolaMiau is known as a narrowly endemic species of Yingde city in the central north of Guangdong[7].

Danxiashan mountain is known as Red Stone Park of China[8], and has now become a national park and a natural World Heritage Site. In Danxiashan mountain a typical Danxia landform characterized by red-colored sandstones and conglomerates, providing unique habitats for some endemic species here, such asFirmianadanxiaensisH. H. Hsue et H. S. Kiu,ViolahybanthoidesW. B. Liao et Q. Fan[9],DanxiaorchissingchianaJ. W. Zhai, F. W. Xing et Z. J. Liu[10]. From 2004 to present, we have taken continuous biological surveys on Danxiashan mountain in order to elucidate the biodiversity patterns of Danxia landforms[11]. During the field survey, a distinctDiospyrosspecies was collected in Danxiashan mountain. After two years of field observations, we confirmed it was a new species, which was described and illustrated below.

1 Materials and methods

All the specimens used for this study were collected from Danxiashan, Guangdong Province. Morphological data for description of the new species were observed and measured based on fresh and dry specimens using a micrometer and a stereomicroscope from 2014 to 2016. The voucher specimens were deposited in SYS, IBSC (acronyms according to Thiers 2016+).

2 Diospyros penghuae W.B. Liao,

Q. Fan et W.Y. Zhao Taxonomy Treatment:—DiospyrospenghuaeW.B. Liao, Q. Fan et W.Y. Zhao,sp.nov. (Fig. 1, Fig. 2)

Type:—China. Guangdong Province: Renhua County, Danxiashan mountain, Xianglonghu, foot of the mountain, in dense forest, 119 m, 25°01′N, 113°44′E, 9 Sep. 2015 (fr.),W.-Y.Zhaozwy-34 (holotype: SYS! isotypes: SYS! IBSC!).

Diagnosis:—Similar toD.cathayensis, but differs by shrubs evergreen, branchlets without spines, leaf blade elliptic to obovate-elliptic, margin revolute, stamens villose, glabrescent, styles 4 cleft to ovary, staminodes 3, fruiting pedicel 1.3～2.6 (～3.1) cm, seeds 3-sided or subreniform.

Description:—Evergreen shrubs, rarely small trees, 2～3 (5) m tall, 1～4 cm in diameter. Branchlets brown, slender, terete, young branchs densely puberulent, never tipped with spines. Petiole 3～6 mm, puberulent; leaf blade elliptic to obovate-elliptic, ((4.0) 5.3～12.5 (14.0) )cm× ((1.6) 2.2～4.4 (5.3)) cm, thin leathery, base cuneate, apex obtuse, rounded or slightly blunt; adaxially dark green and lustrous, abaxially yellow-green, pubescent along midrib, lateral veins 4～9 per side, puberulent when young; reticulate veinlets slender and raised both surfaces, obvious, leaf margin revolute. Staminate flowers cymes (seldom solitary), per cymes three flower, peduncles 2～7 mm, pedicel 3～7 mm (1.1 mm when solitary), pubescent; calyx lobes 4, divided nearly to base, triangular or ovate, 1.5～7 mm; corolla pale yellow, urceolate, 3.5～5.5 mm, pubescent on both surfaces, lobes 4, ovate, ca. 1mm, reflexed; stamens 16, per two stamens symphysis, with sparsely villose, then glabrescent. Pistillate flowers: pedicel 8～14 mm, pubescent; cayx lobes 4, ovate, ca. 1 cm, puberulent; corolla pale yellow, pubescent on both surfaces, tube ca. 4mm, lobes 4, ovate or triangular, 1.5～2.5 mm; staminodes 3, glabrous; styles 4, divided to base, stigma 2-cleft; ovary villose. Fruiting pedicel 1.3～2.6 (3.1) cm, slender, densely puberulent. Fruiting calyx 4, divided to nearly base, slightly reflexed, subglabrous; lobes ovate or oblong-lanceolate, (1.1 ～1.5) cm × (4.5 ～ 9) mm, leathery, apex obtuse, veins several, subparallel, slightly raised. Berry orange, globose, 1.4～2 cm in daim, sparsely hairy. Seeds 1～8, brown, 3-sided or subreniform, ca. (8～12) mm× 6.5 mm× 4 mm.

Etymology:—The specific epithet is in honor of Prof. Hua Peng (1956-2018) of Sun Yat-sen University, chairman of Red Beds and Danxia Geomorphology Working Group of IAG, who made a great contribution in Danxia landform research.

Phenology:—Flowering March to May and fruiting July to November.

Distribution and habitat:—Diospyrospenghuaeis widely distributed in Mount Danxia, Renhua County, Guangdong Province, China. And usually distributed in dense forests or ravines where soil forming rock is red-colored sandstones, at altitudes of 90～260 m. The associated species includedCastanopsisjucundaHance,OsteomelessubrotundaK. Koch,PittosporumfulvipilosumH. T. Chang et S. Z. Yan,RhuschinensisMill.,Diplosporadubia(Lindl.) Masam.,NandinadomesticaThunb., andStemonatuberosaLour. In addition,Diospyrospenghuaeis diecious and the female and male ratio about 1/3.5 according to our field observation in April 2015.

Additional specimens examined (Paratypes):—China. Guangdong Province: Renhua County, Danxiashan mountain, Xianglonghu, foot of the mountain, in dense forest, fruit, 125 m, 25°01′ N, 113°44′ E, 3 Sep. 2014,Q.Fan12702 (SYS! IBSC!); ibid, pistillate flower, 9 Apr. 2015,W.-Y.Zhaozwy-59 (SYS! IBSC!); Danxiashan mountain, hill slope near the Sengmaofeng, pistillate flower, 117 m, 25°01′N; 113°45′ E, 8 Apr. 2015,W.-Y.Zhao&Z.-X.Chenzwy-48; ibid, staminate flower,W.-Y.Zhao&Z-X.Chenzwy-49 (SYS! IBSC!)； Danxiashan mountain, hill slope near the Danxiashanzhuang, pistillate flower, 120m, 25°01′ N; 113°45′E, 8 Apr. 2015,W.-Y.Zhao&Z.-X.Chenzwy-52; ibid, staminate flower, 8 Apr. 2015,W.-Y.Zhao&Z.-X.Chenzwy-54 (SYS! IBSC!)；Danxiashan mountain, hill slope near the Xianglonghu, Aiqinggu, pistillate flower, 125m, 25°01′ N; 113°45′ E, 9 Apr. 2015,W.-Y.Zhaozwy-60; ibid, staminate flower, 9 Apr. 2015,W.-Y.Zhaozwy-61 (SYS! IBSC!)； Danxiashan mountain, hill slope of the Wolonggang, fruit, 137 m, 25°01′ N; 113°45′ E, 20 Nov. 2015,Q.Fan14038 (SYS! IBSC!).

Fig.1 Diospyros penghuae W.B. Liao, Q. Fan et W.Y. Zhao(A-C: Branch with pistillate flower, staminate flower, fruit; D-E:Staminate flower; F: Stamen; G: Calyx lobes of staminate flower; H: Pistillate flower, front view; I: Corolla of pistillate flower; J: Ovary; K: Stigma;L: Calyx of pistillate flower; M: Fruit; N: Fruiting calyx; O: Cross section of fruit; Iillustration is drawn by Liu Yunxiao)

Fig.2 Morphological characters of Diospyros penghuae W.B. Liao, Q. Fan et W.Y. Zhao (A: Habit of plant; B: Staminate flower; C:Pistillate flower; D: Fruit; E: Cross section of fruit; F: Stamens of staminate flower, and vestigial ovary; G: Stamens of staminate flower, per two stamens symphysis.)

3 Discussion

Currently, the infrageneric classification ofDiospyrosis still not very clear. Furthermore, some taxonomic study and phylogenetic analysis of genusDiospyroswere primarily based on species distributed in Pacific region[12], Africa[13], India[14]and New Caledonian[3]. However, the species endemic to China were not included in these studies. The new speciesD.penghuaedescribed here is similar toDiospyroscathayensisSteward[15],D.armataHemsley[16],D.rhombifoliaHemsley[16],D.reticulinervisC. Y. Wu[17],D.caloneuraC. Y. Wu[17], andD.tutcheriDunn in the raised leaf venation, long slender pedicels and conspicuously veined, spreading or slightly reflexed, and leathery or papery calyx lobes. This resemblances might represent an infrageneric evolution clade[4].

D.cathayensisis the closest species relative toD.penghuaebased on morphology. However,D.penghuaeis readily distinguished fromD.cathayensisby the shrub (vs. small tree) habit, the non-spiny (vs. inconspicuous spiny) branchlets, the different leaf shape (elliptic to obovate-elliptic vs. elliptic) and size ((5.3～12.5) cm × (2.2～4.4) cm vs. (4～9)cm ×(1.5～3.6) cm), the shorter fruiting pedicels (1.3～2.6 cm vs. 2.5～4 cm), the smaller fruits (1.4～2 cm vs. 1.5～3 cm in diam.) and the inconspicuous (vs. beak shaped) hilum.D.rhombifoliaalso has many features in common withD.penghuae, but has stout leafless branch spines, 4-sporangiate (vs. 8-sporangiate) ovary, 2 (vs. 4) styles, hemispherical or trigonous (vs. 3-sided or subreniform) seeds. In addition,D.rhombifoliais a deciduous tree species reaching 5～8 m in height, however, the latter is an evergreen shrub species only 2～3(5) m tall (Table 1).

Table 1 Morphological differences between Diospyros penghuae sp. nov., D. rhombifolia and D. cathayensis