Athyrium aberrans Liang Zhang & Li Bing Zhang, 2022

Qiu, Yong-Ling, Zhang, Lin, Zhang, Li-Bing, Zhou, Xin-Mao & Zhang, Liang, 2022, Athyrium aberrans (Athyriaceae), a new species of the lady ferns from southeastern Xizang, China, based on morphological and molecular evidence, Phytotaxa 533 (3), pp. 165-172 : 167-168

Athyrium aberrans Liang Zhang & Li Bing Zhang , sp. nov. ( Figure 2 ).

Type:— CHINA. Xizang: Nyingchi , Medog County, Beibeng Xiang , Deergong Village , elev. 1640 to 1650 m, 29°11’N / 95°08’E, on open areas in wetlands, 23 November 2018, Liang Zhang 2929 (holotype KUN1519962 , Figure 3 ; isotypes KUN & PYU!) .

Diagnosis:— Athyrium aberrans is most similar to A. falcatum by having linear-lanceolate and once pinnate laminae, falcate-ovate pinnae, and linear or oblong sori, but differs the latter in having purplish petioles and rachises, finely toothed pinna margins, and a bulbil on the rachis below the lamina apex.

Plants perennial, evergreen, terrestrial. Rhizome short, erect, with many glabrous and black roots. Frond caespitose, 5–10 per rhizome, 20–35 cm tall, 5–6.5 cm wide; petiole black at base, upward purplish, 6–9 cm, 0.8–1.3 mm in diam. at middle, adaxially canaliculated, base scaly, scale light brown, linear-lanceolate, 3.1–4 mm long, 0.5–0.9 mm wide, scattered, margins entire, upper middle parts twisted. Lamina linear-lancoelate, thickly papery, once pinnate, 13–25 × 2.8–6.5 cm, apex acuminate, slightly narrowed toward base from below middle of lamina; rachises 0.4–0.6 mm in diam. at middle, glabrous, purplish, with a scaled bulbil at upper part of rachis, adaxially sulcate. Pinnae (8–)10–19 pairs, 1.4–3.5 × 0.9–1.4 mm, alternate, falcate-ovate, shortly petiolate, subspreading, basal 2-3 pairs of pinnae slightly reflexed and smaller, nearly 2/3 to 4/5 as long as middle ones, pinna apices rounded, bases truncate or cordate and slightly auriculate on acroscopic and basiscopic sides, margins toothed; venation pinnate, visible on both sides, slighted raised abaxially, lateral veins free, 10–14 pairs, forked. S ori linear or oblong, 8–13 pairs per pinna, 2–4.5 mm long, close to midribs, basal 2–6 pairs of pinnae often sterile; indusia linear or oblong, the same length as sori, membranous, entire, persistent. Spores bilateral, elliptic in polar view, bean-shaped in equatorial view; perispore surface with papillate microstructure on rugulose ornamentation.

Additional specimens examined (paratype):— CHINA. Xizang: Nyingchi, Medog County, Beibeng Xiang , Deergong Village , elev. 1640 to 1650 m, 29°11’N / 95°08’E, wetlands in forests, 22 June 2021, Liang Zhang et al. 4401 ( KUN!, PYU!) .

Geographical distribution:—Currently, Athyrium aberrans is only found in Medog County, Xizang, China and may represent a species endemic to Xizang, China.

Ecology: — Athyrium aberrans was observed to be terrestrial in wetlands in the open areas in the forests of the Deergong Basin, at elevations between 1640 and 1650 m. High humidity and sufficient light are important for the growth of the new species.

IUCN Red List category: —Only two populations with about 40 individuals of Athyrium aberrans were found. The status of the new species can be classified as Critically Endangered (CR), based on current information and following the International Union for Conservation of Nature and Natural Resources (IUCN) guidelines (IUCN, 2011), but more extensive fieldwork focusing on the similar habit of the type locality in the nearby mountains is needed to accurately assess its conservation status.

Etymology: — The species epithet from the Latin, aberrans, abnormal, referring to purplish stipe and rachis and scaled bulbil of the new species which is uncommon in the genus. Besides, the new species could be confused with some species of Diplazium Swartz (1801: 61) , D. longifolium T. Moore (1857: 141) for example.

Vernacular name: — ǿ异fiǎƀ (qi yi ti gai jue, which means a special species of Athyrium ).

Figures

FIGURE 2. Athyrium aberrans Liang Zhang & Li Bing Zhang.—A. Habit.—B. Adaxial lamina.—C.Abaxial lamina, an arrow indicates a bulbil on the rachis.—D. Portion of pinnae showing sori and veins.—E. Rhizome with petiole bases.—F. Spore.

FIGURE 3. Holotype of Athyrium aberrans Liang Zhang & Li Bing Zhang.