Pteris pseudoamoena D. M. Yang & R. Guo. Drawn 2022, sp. nov.

Pteris pseudoamoena D. M. Yang & R. Guo, sp. nov. Figs. 1–3.

Type:— CHINA. Guangxi Province, Chongzuo City, Longzhou County, Banbi Village, under jungles in calcareous hills, 22.31°N, 106.99°E, elev. 270 m, 30 January 2015, J. M . Wang 20150130-2 (holotype, IBSC!; isotypes, IBSC!), J. M . Wang 20150130-3 (paratype, IBSC!), J. M . Wang 20150130-4 (paratype, IBSC!); CHINA, Guangxi Province, Chongzuo City, Daxin County, Xialei Nature Reserve, on dry calcareous rocks, 22.91°N, 106.75°E, elev. 545 m, 31 January 2015, J. M . Wang 20150131-4 A7 (paratype, IBSC!), J. M. Wang 20150131-4 A8 (paratype, IBSC!).

Diagnosis:— Morphological features of the new species are similar to those of P. amoena Blume (1828: 210) and P. mcclurei Ching (1933: 28) with tripinnatifid laminae, but differ by having spores with echinate-tuberculate and auriculate ornamentation, strawcolored stipes, rachises and costae, free veins but occasionally interlinked veins, while P. amoena having spores with tuberculate and verrucate ornamentation, castaneous-brown to sorrel-red stipes, rachises and costae, and free veins, and P. mcclurei having spores with rugulate ornamentation, castaneous-brown to lightly brown stipes, rachises and costae, and interlinked veins (Table 2, Figs. 2 & 3).

Description:— Terrestrial, 65–130 cm tall. Rhizomes erect or ascending, short, 0.8–1.5 cm in diam., clothed with brown scales. Stipes, rachises and costae straw-colored, or stipes light brown at base, the upper parts, rachises and costae straw-colored. Stipes 32–65 cm long, 3–6 mm in diam., scaly at base, upper parts glabrous; laminae ovate, tripinnatifid, 26.6–58 × 36.6–55.5 cm, papery when dried; lateral pinnae 3–8 pairs, opposite or subopposite, obliquely extended; basal pinnae with 1–2 pairs of basiscopic pinnules, 13.3–29 × 3.3–6.5 cm, with 0.5–2.5 cm long petiolules; upper pinnae lanceolate, pectinate, sessile or subsessile, sometimes with one pair of basiscopic pinnules; middle pinnae 12–20 × 2.2–5 cm, base cuneate and slightly oblique, apex caudate, 1–6 cm long; terminal pinnae similar but slightly wider and with 2–5 cm long petiolules; segments 15–30 pairs, alternate, 2–7 mm apart, subfalcate, 1–3.5 × 0.4–0.6 cm, base slightly expanded and decurrent, sterile margins lightly serrulate, apex obtuse or mucronate, basal segments of pinnae slightly shorter; costae prominent and glabrous on the abaxial side, grooved on the adaxial side, with short spines along grooves and the base of midribs; veins decumbent, forked, free, or 2 opposite veins at the base of segments interlinked into a triangular mesh, and other veins outward from the mesh separate. Sori linear, along pinna margins. Spores tetrahedral, 37.2 × 31.6 μm, with echinate-tuberculate and auriculate ornamentation on the surface.

Distribution and Habitat:— Pteris pseudoamoena is currently found in Longzhou County and Daxin County of Guangxi Province, China, and in Kim Hy Nature Reserve of Bac Kan, Vietnam. It grows in calcareous hills with elevation 216– 600 m.

Etymology:— The specific epithet refers to the most similar species P. amoena of the new species.

Common name (assigned here):— Ni Hong Gan Feng Wei Jue (IJḢ杆Ṃ尾ae; Chinese name).

Conservation status:— Pteris pseudoamoena is currently found in two counties of Guangxi, China and one location in Vietnam, and short of a profound study. According to the IUCN Red List criteria (IUCN 2012), it is considered data deficient (DD). Due to its current narrow geographical distribution, further investigations are still needed.

Phylogenetic evidence:— A maximum likelihood tree, Bayesian phylogenetic tree and maximum parsimony tree were constructed based on the sequences of P. pseudoamoena and other Pteris samples (Fig. 4). It is found that P. pseudoamoena is sister to a clade consisting of P. amoena, P. nakasimae and P. mcclurei. The new species forms a lineage independent from the other Pteris samples.

Other specimens examined:— CHINA, Guangxi Province, Chongzuo City, Longzhou County, Xiangshui Town, Siqing Village, in calcareous hills, 22.45°N, 107.11°E, elev. 216 m, 23 October 2019, S. L . Jin JSL7327 (CSH). CHINA, Guangxi Province, Chongzuo City, Longzhou County, in calcareous hills, 2019, S. L . Jin JSL7342 (CSH, KUN). CHINA, Guangxi Province, Chongzuo City, Daxin County, Xialei Town, Renyi Village, in calcareous rock crevices under jungles, 22.88°N, 106.76°E, elev. 541 m, 28 April 2014, S. L . Jin YYH13555 (CSH); ibid., elev. 520–600 m, 2016, S. L . Jin JSL4188 (CSH), S. L . Jin JSL4198 (CSH), S. L . Jin JSL4503 (CSH), S . L. Jin JSL4504 (CSH), S. L. Jin JSL4508 CSH), S. L. Jin JSL4509 (CSH), S. L. Jin JSL4509A (CSH), S. L. Jin JSL4512 (CSH), S. L. Jin JSL4517 (CSH), S. L. Jin JSL4522 (CSH); ibid., elev. 550 m, 20 May 2008, HCAS GX Exp ed. 0792 (IBK); ibid., elev. 600 m, 11 August 2008, HCAS GX Exped. 2676 (IBK). VIETNAM, Bac Kan, Na Ri, An Tinh Com., Kim Hy NR., Na Duong Village, inside a cave, elev. 300–530 m, 3 December 2013, L. B. Zhang, L. Zhang & T. N. Lu 6661 (CDBI).