Polystichum asiae-minoris Tunçkol & Li Bing Zhang, 2020

Tunçkol, Bilge, Yaşayacak, Hasan, Liang, Zhen-Long, Aksoy, Necmi & Zhang, Li-Bing, 2020, Polystichum asiae-minoris (Dryopteridaceae), a new fern from Kastamonu, Turkey, Phytotaxa 447 (4), pp. 296-300 : 296-299

Polystichum asiae-minoris Tunçkol & Li Bing Zhang , sp. nov. ( Figs. 1 , 2 ).

Type: — TURKEY. Kastamonu: Küre Mountains National Parks, Horma Canyon, Limestone Bedrock, 41°38’04’’N, 33°08’35’’E, elev. 800 m, 20 July 2018, B. Tunçkol T 4500 (holotype CDBI!, isotypes ISTO-38328!).

Diagnosis: — Polystichum asiae-minoris is somewhat similar to P. obliquum (D. Don 1825: 3) T. Moore (1858: 87 , 98) in having oblique-oblong pinnae and sharing same plant size, but the former has laminae oblanceolate (vs. lanceolate in the latter), pinnae with broad-type microscales (vs. narrow-type microscales in the latter), sori closer to pinna margins (vs. medial in the latter), basal petioles blackish (vs. brown or stramineous in the latter).

Plants perennial, evergreen, (18–)12–18(–20) cm tall. Rhizomes ascending, ca. 2 cm long, ca. 1.5 cm diam., with remnant bases of old petioles; roots dull brown when dried, up to 10 cm long, ca. 0.5 mm diam. Leaves in tufts; petioles 4–7 cm long, ca. 1.2 mm diam., basal portions covered with scales; proximal petiole scales ovate to ovate-lanceolate, 1.4–3.6 × 0.9–1.8 mm, papery, dull brown, margins fimbriate, apex acuminate; distal petiole scales ovate-lanceolate, 2.2–3 × 0.5–1 mm, membranous, margins weakly fimbriate and fimbriae narrow- to broad-based, apex long-acuminate or caudate.Laminae oblanceolate, 1–pinnate, (4–) 7–12 cm, apex acuminate; rachises ca. 0.9 mm diam., brown, adaxially sulcate; rachis scales of two types, the first ovate or ovate-lanceolate, light brown, up to 1.5 mm long including tip, 0.5 mm wide at base, margins with irregular outgrowths, fimbriate, apex long-caudate; the second bristle-like, ca 1 mm long, margins entire and fimbriate at base. Pinnae in 5–8 pairs, alternate, auriculate, separate from each other, 2–13 mm apart, oblique-oblong, papery, base cuneiform, largest pairs 1.2–1.6 × 0.4–0.6 cm, above center of lamina, basal pinnae progressively narrower, basal pair reflexed; proximal margins not overlapping rachis, basiscopic margins cartilaginous and shallowly toothed, acroscopic margins nearly entire and forming a (60–)90–110° angle with rachis, apex acute; basal pinnae with undulate or entire margins and obtuse apex; pinna petioles 0.5–1 mm long; adaxially glabrous; abaxially with dense microscales; microscales broad-type, ovate or ovate-lanceolate, or lanceolate, whitish brown, 0.5–1(–1.5) mm long, 0.15–1.5 mm wide at base, margins subentire; costa sunken abaxially and protruding adaxially, veins obscure and invisible both sides, lateral veins free, forked. All pinnae fertile; sori terminal on lateral veins of fertile pinnae, 0.8–1.2 mm diam., submarginal (centers of sori 1–1.5 mm from pinna margins, 0.7–3.5 mm from midrib), 2–6 on acroscopic side and 6–8 on distal basiscopic side, centers 1–1.5 mm apart from one another; indusia absent.

Geographical distribution:— Polystichum asiae-minoris is known only from Horma Canyon in Küre Mountains National Park, in north-central Turkey.

Habitat:— The new species was observed to be epilithic on limestone bedrock, in humid and shady conditions.

IUCN Red List category:— The new species is only known from its type locality. There were only ca. 110 individuals observed in the field. This area is one of the 100 Forest Hotspots of Europe that should be protected and it is also one of the nine hotspots of Turkey. Yet, with the new wooden walkway in the Canyon opened up for tourism, the status of the new species should be Critically Endangered (CR) category based on current information and following IUCN ( IUCN Standards and Petitions Subcommittee 2017).

Etymology:— From the Latin, asiae-minoris , Asia Minor, referring to its geographical origin.

Vernacular name:— Kanyon Eðreltisi.

Figures

FIGURE 1. Polystichum asiae-minoris Tunçkol & Li Bing Zhang.—A. Plant habit.—B. Leave.—C. Pinnae.—D. Rachis scale.—E. Scale from middle of petiole.—F. Scale from base of petiole. A–F drawn by ZLL based on the holotype (Scale A, B, C=1 cm; D=0.5 mm; E & F=1 mm).

FIGURE 2. Polystichum asiae-minoris Tunçkol & Li Bing Zhang.—A. The canyon where the new species was discovered.—B–D. Habit in the field.—E. Lower portion of plant.—F. Upper portion of adaxial leaf surface.—G. Lower portion of adaxial leaf surface.—H, J, K. Portions of abaxial leaf surfaces.