Polystichum suiyangense Bo Wang, Q. W. Sun & Li Bing Zhang 2022, sp. nov.
Creators: name: Wang, Bo
name: Sun, Qing-Wen
name: Wang, Ze-Huan
name: Chen, Chun-Ling
name: Xu, Wen-Fen
name: Zhang, Li-Bing
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Polypodiopsida
Polypodiales
Dryopteridaceae
Polystichum
Polystichum suiyangense

description: Polystichum suiyangense Bo Wang, Q.W.Sun & Li Bing Zhang, sp. nov. (Figs. 1 & 2).
Type: — CHINA. Guizhou Province: Suiyang County, Jianba Town, Guanyinyan, 28°5′15″N, 107°4′49″E, elev. ca. 830 m, 17 June 2018, Bo Wang wb-201806088 (holotype GZTM!; isotypes CDBI!, GZTM!).
Diagnosis: —The new species is most similar to Polystichum martinii Christ (1902: 263), but differs from the latter in having leathery and dark green laminae (vs. papery and yellowish green laminae), densely scaly (vs. sparsely scaly) petioles and rachises with scales that are brown to bicolor and chartaceous (vs. brown and membranous), and pinnatipartite pinnae (vs. pinnatipartite to pinnatisect pinnae). The new species is also similar to P. auriculum Ching (1949: 309), and differs from the latter in having leathery and dark green laminae (vs. papery and yellowish green laminae), densely scaly (vs. sparsely scaly) distal petioles and rachises with scales that are brown to bicolor and chartaceous (vs. brown to dark brown or castaneous and thick-membranous), pinnatipartite pinnae (vs. pinnatilobate to pinnatisect pinnae), and nearly medial sori (vs. marginal sori). The new species is further similar to P. bifidum Ching (1958: pl. 242), but differs from the latter in having petioles of ca. 1/5 of the laminae in length (vs. ca. ½ of the laminae in length), dark green (vs. green laminae, dense petiole and rachis scales (vs. sparse petiole and rachis scales), rounded pinna apex (vs. acute pinna apex), entire auricles (vs. lobed auricles) (Table1).
Description:—Plants perennial, evergreen, 12–26 cm tall. Rhizome erect, short, ca. 1.2 cm in diam. including stipe bases, with base of remnant old petioles. roots up to 15 cm long, 2–3 mm in diam. Fronds cespitose, 6–12 per rhizome. Fronds 12–25 cm; petiole 3–8 cm long, 0.5–1.2 mm in diam. at base, adaxially canaliculate, stramineous, densely covered with scales; scales brown to bicolor, lanceolate to long triangular lanceolate, ca. 3–4.5 × 0.6–1 mm, chartaceous, margins shortly fimbriate or only with short teeth, apex acuminate to caudate, matte; scales on distal petiole similar but narrower. Lamina long lanceolate, 7–19 × 2–3.5 cm, caudate acuminate towards the apex uncontracted or slightly contracted towards base, 1.5–2.5 cm wide at base, dark green, nearly concolorous on both surfaces; rachis 0.4– 0.8 mm in diam. about its middle, stramineous, without proliferous bulbils, adaxially sulcate, densely scaly, gradually sparse upwards, scales similar to stipe scales but narrower; 1-pinnate-pinnatifid. Pinnae 12–22 pairs, 1.5–2.3 × 0.6–1 cm, alternate, shortly petiolate, pinnatipartite, nearly rectangular, leathery, lower pairs obliquely ovate or nearly oblong attached almost at right angles to the rachis, upper pairs shorter and ovate or nearly long ovate, spreading to slightly ascending, acroscopic base auriculate, basiscopic base cuneate, apex acute and terminating without mucronate spine; lobes 4–6 pairs, lobes ascendant, obovate, bases narrowly cuneate, apices 1–2-toothed or no teeth, apices of lobes acute apically, basal acroscopic lobes obviously largest; adaxially glabrous, abaxially sparsely scaly; microscales light brown, linear-lanceolate to lanceolate, ca. 0.5 × 1.2 mm, margin serrated. Lamina texture leathery; venation pinnate, lateral veins dichotomous on auricles and other lobes, slightly distinct abaxially, indistinct adaxially. Sori small, ca. 1 mm in diam. when mature, abaxial and terminal on veinlets, nearly medial; indusia present, light brown, entire, evanescent.
Distribution and ecology:— Known only from the type locality at an elevation of ca. 830 m. This population grows in karst limestone under the canopy of a broad-leaved forest dominated by Schefflera delavayi (Franchet 1896: 307) Harms (1900: 486) (Araliaceae), and accompanied by Polystichum alcicorne (Baker 1888: 229) Diels (1900: 194) (Dryopteridaceae), Polystichum dangii P.S. Wang (2001: 531) (Dryopteridaceae), Dryopteris bodinieri (Christ 1902: 248–250) C. Christensen (1905: 204) (Dryopteridaceae), Ctenitis subglandulosa (Hance 1866: 253) Ching (1938: 302– 304) (Dryopteridaceae), Elatostema sp. (Urticaceae), etc.
IUCN Red List category: —Following the IUCN Red List Categories and Criteria (IUCN, 2017), Polystichum suiyangense is assessed as CR (Critically Endangered) based on the fact that only one population with fewer than 50 individuals was found in the field.
Etymology:— Derived from the type locality, Suiyang (Guizhou, China).
Vernacular name: —OiḆH¨ (sui yang er jue).
Additional specimens studied (paratypes):— CHINA. Guizhou: Guiyang city, Guizhou University of Traditional Chinese Medicine Germplasm Garden, cultivated, 17 June 2018, Bo Wang wb-201806087, introduced by Bo Wang from the type locality (GZTM); CHINA. Guizhou: Suiyang County, Jianba Town, Guanyinyan. 25th March 2022, Bo Wang wb-202203001 (GZTM).
description: Published as part of Wang, Bo, Sun, Qing-Wen, Wang, Ze-Huan, Chen, Chun-Ling, Xu, Wen-Fen & Zhang, Li-Bing, 2022, Polystichum suiyangense (sect. Sphaenopolystichum, Dryopteridaceae), a new fern from Guizhou, China, pp. 93-99 in Phytotaxa 567 (1) on pages 94-97, DOI: 10.11646/phytotaxa.567.1.9, http://zenodo.org/record/7138073