Polystichum hainanicola Li Bing Zhang, Liang Zhang & X.F.Gao, 2013
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publication ID |
https://doi.org/ 10.11646/phytotaxa.85.1.2 |
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persistent identifier |
https://treatment.plazi.org/id/03CC1843-FFA5-FA5E-75B9-1683155BFE59 |
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treatment provided by |
Felipe |
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scientific name |
Polystichum hainanicola Li Bing Zhang, Liang Zhang & X.F.Gao |
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sp. nov. |
Polystichum hainanicola Li Bing Zhang, Liang Zhang & X.F.Gao View in CoL , sp. nov. ( Figures 1 View FIGURE 1 , 2 View FIGURE 2 )
Polystichum hainanicola is most similar to Polystichum guangxiense W.M.Chu & H.G.Zhou in Zhou et al. (1996: 205), but the former has pinnae with a length to width ratio of 2.5–2.7:1, lamina completely fertile and sori fewer than four above midrib of middle pinnae. In contrast, the latter has pinnae with a length to width ratio of ca. 3:1, lamina sterile in its lower portion, and sori 6–11 above midrib of middle pinnae.
Type:— CHINA. Hainan Province: Dongfang County, Guangba Town , Nanlang Cun , Jiulong Shan , 19°01'N /109°.09' E , on limestone cliffs, 1–3 m above the ground, 780–821 m, 10 November 2010, Liang Zhang 1331 (holotype CDBI!, isotypes CDBI!, CTC!, MO!) .
Plants perennial, evergreen. Rhizomes ascending, 0.8–1.8 cm long, ca. 7 mm in diam., with remnant bases of old stipes, scaly; scales ovate-deltate or broad lanceolate, 1.15–1.85 × 0.50–0.85 mm, brown, margins nearly entire, with few short outgrowth and shortly ciliate; roots dull brown when dry, up to 17 cm long, 0.22–0.43 mm in diam., nearly glabrous or densely covered with short lanate hairs. Fronds caespitose, 4–10 per rhizome, appressed to the substrate or slightly ascending, (13.5–) 20.1–35.6 cm long; stipes green, (3.6–) 6.7–10.5 cm long, 0.63–1.22 mm in diam. at middle, adaxially canaliculate, scaly; basal stipe scales ovate-deltate or lanceolate, chartaceous, 1.80–3.15 × 0.60–0.95 mm, brown, concolorous, apices caudate, margins nearly entire or slightly ciliate, with irregular dentate outgrowths; distal stipe scales similar to basal stipe scales but narrower, 1.2–2.8 × 0.4–0.7 mm, chartaceous, brown, apices caudate, margins with short outgrowths. Laminae oblanceolate, once pinnate, (8.7–)12.9–24.3 × 3.1–4.3 cm, apices acute or rounded, slightly narrowed toward base from below middle of lamina; rachises 0.59–0.84 mm in diam. at middle, apices without proliferous bulbil, green (same color as pinnae) when fresh, turning yellowish green when dry, adaxially sulcate, scaly abaxially; rachis scales lanceolate or broadly subulate, light brown, nearly transparent, 1.25–2.65 mm long, base 0.25–0.58 mm wide, differing in length, membranaceous, margins sparsely toothed, apices caudate. Pinnae (8–)18–22 pairs, oblong, 16.9–18.6 × 7.1–9.4 mm, basalmost pairs slightly narrowed, nearly 2/3 to 4/5 as long as middle ones, papery, shortly petiolate, basoscopic margins at angles of 95–120 degree with rachis, alternate, apices rounded, bases broadly cuneate with basoscopic side being narrower and forming an 80-degree angle with acroscopic side, distal acroscopic margins shallowly undulate, undulations 3–4, ca. 0.2 mm tall in middle and non-mucronate, acroscopic bases auriculate, auricles deltate, 3.7–5.1 × 3.1–3.4 mm, basoscopic margins entire, curved; adaxial surface green when fresh, dull green when dry, almost glabrous, abaxial surface sparsely covered with microscales; microscales narrow, linear or subulate, brown, 1.1–2.9 mm long, 0.11–0.18 mm wide at base; venation pinnate, visible abaxially and slightly obscure adaxially, lateral veins free, single or forked. Sori terminal on lateral veins, 4–8 on acroscopic side, 1–4 on distal basoscopic side, 1.4–2.4 mm in diam., close to pinna margins (centers of sori 0.6–0.8 mm from pinna margins, 1.8–3.1 mm from midrib), centers ca. 1.2 mm apart from one another; indusia peltate, (0.3–) 0.8–1.2 mm in diam., membranous, brownish, margins irregularly lacerate, early deciduous. Sporangia round, ca. 0.24 mm in diam., walls ca. 0.017 mm thick, dark brown when mature; annuli with ca. 15 thickened cells; stalks ca. 0.31 mm long.
Geographical distribution:— Polystichum hainanicola is known only from Jiulong Shan in adjacent Guangba and Wangxia towns in western Hainan. Jiulong Shan is a limestone mountain along Changhua Jiang, the second largest river in Hainan. Along the river there are a number of such limestone mountains. It is possible that the new species occurs in additional limestone mountains around Changhua Jiang in western Hainan that are yet to be explored.
Ecology:— Polystichum hainanicola grows in wet limestone cliffs in rainforests, at elevations between 780 and 825 m.
The plants that accompanied Polystichum hainanicola include: the seed plants Impatiens hainanensis Chen (1987: 9 ; Balsaminaceae ) and Primulina sp. (Gesneriaceae) ; the fern species Adiantum capillus-veneris L. fo. dissectum (M.Martens & Galeotti) Ching (1957: 344), A. gravesii Hance (1875: 197) , A. malesianum Ghatak (1963: 73) , Aleuritopteris squamosa (Hope & C.H.Wright) Ching (1941: 199) , Aleuritopteris sp. , Pteris morii Masamune (1942: 242) , P. ensiformis Burman f. var. victoriae Baker (1890: 576 ; Pteridaceae ) and Tectaria zeilanica (Houtt.) Sledge (1972: 422 ; Tectariaceae ).
IUCN Red List category:—Only five populations with about 60 individuals of Polystichum hainanicola have been found. The status of the new species is likely to be classified as Critically Endangered, based on current information and following the IUCN (The International Union for Conservation of Nature and Natural Resources) guidelines ( IUCN 2008), but more extensive fieldwork in surrounding similar habitats is needed to accurately assess its conservation status. The preservation of the rain forests of Hainan is a key factor for the conservation of this species. Fortunately, the habitats are well protected.
Etymology:—The species epithet is from the Chinese pinyin, hainan, the name of a province in southernmost China, and the Latin suffix -cola, inhabiting, referring to the province where the type was collected.
Additional specimens examined (paratypes):— CHINA. Hainan Privince: Dongfang County, Guangba Town , Nanlang Cun , Jiulong Shan , 19°01'N /109°.09' E , on limestone cliffs, alt. 1000 m, 4 May 2004, Xinsheng Qin & Rongjing Zhang 533 ( IBSC, PYU!) .
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