Polystichum malipoense Li Bing Zhang, M.Q.Han & Yan Liu, 2018

Polystichum malipoense Li Bing Zhang, M.Q.Han & Yan Liu View in CoL , sp. nov. ( Figures 7 View FIGURE 7 , 8 View FIGURE 8 )

Type:— CHINA. Yunnan: Malipo County, Xiajinchang Town, Xinyan Village , inside a limestone cave, alt. 2050 m, 23°07 ′ 04 ″ N, 104°47 ′ 30 ″ E, 31 March 2017, Mengqi Han HMQ1356 (holotype IBK! GoogleMaps , isotypes CDBI! GoogleMaps , IBK! GoogleMaps , MO! GoogleMaps ).

Diagnosis:— Polystichum malipoense is unique in P. sect. Haplopolystichum known so far by having the broadest pinnae being oblique-ovate.

Plants perennial, evergreen, 30–36 cm tall. Rhizomes unseen; roots dull brown when dried, up to 9 cm long, ca. 0.4 mm diam. Leaves in tufts, 5–14 per rhizomes; petioles 15–18 cm long, 1.5–2.2 mm diam., basal portions covered with scales, scales ovate-lanceolate, 2.2–2.8 × 1–1.5 mm, papery, dull brown, edges nearly entire, apex acuminate; distal petiole scales ovate, ovate-lanceolate, 0.3–3.6 × 0.18–1.8 mm, membranous, margins with irregular teeth, apex caudate. Laminae lanceolate, 1-pinnate, 16–19 × 3.3–4 cm, apex acuminate; rachises ca. 1.5 mm diam., scales ovate or ovate-lanceolate, dull brown, 1.8–3.3 mm long including tip, 0.5–1.8 mm wide at base, margins with irregular teeth, apex long-caudate. Pinnae 16–19 pairs, oblique-deltoid, 2–2.3 × 1.1–1.3 cm, basalmost pair slightly smaller, basalmost two pairs 1.3–1.8 cm apart, middle pairs 1–1.1 cm apart, all pinnae subcoriaceous, alternate, overlapping rachis, basiscopic margins “S”-shaped, entire, acroscopic margins serrate, basiscopic margins forming a 60–80(–100)° angle with rachis, apex acute, base cuneate and asymmetric, acroscopic sides much broader, pinna petiolues ca. 0.7 mm long, auricles rounded at apex, abaxially with microscales, microscales broad-type, subulate, lanceolate or ovate-lanceolate, light brown, 0.36–0.65 mm long, 0.1–0.18 mm wide at base, margins with irregular teeth; adaxially glabrous; veins visible abaxially but somewhat obscure adaxially, lateral veins free, single or forked. All pinnae fertile; sori terminal on lateral veins of fertile pinnae, 5–13 in 1–2 rows on acroscopic side, 5–6 in 1–2 rows on distal basiscopic side, 1.4–1.8 mm diam., closer to pinna margins than to costa (centers of sori 1.4–2.6 mm from pinna margins, 1.4–5.4 mm from costa), centers 1.4–2.9 mm apart from one another; indusia rounded, dull brown, ca. 1 mm diam., margins erose.

Geographical distribution:— Polystichum malipoense is only known from southeastern Yunnan, Southwest China, bordering northern Vietnam. It is likely endemic to the cave in Malipo County.

Ecology:— Polystichum malipoense grows inside a limestone cave at an elevation of 2050 m with humid and shady conditions.

IUCN Red List category:—CR-Critically Endangered: Only one population with about 50 plants was seen in the field.

Etymology:—The species epithet is based on the Chinese pinyin, malipo, the county name in southeastern Yunnan, and the Latin suffix- ense, of origin, referring to the type locality and the current known distribution of the species in Malipo County, Yunnan.

Vernacular name:—ṀffiDZHẄ(ma li po er jue).

Notes:— Polystichum malipoense is unique in P. sect. Haplopolystichum considering the width of its pinnae and its 1–2 rows of sori on each side of costae. Its pinnae are oblique-ovate which are unusual in the section too. Its petioles are approximately as long as its laminae.