Hypodematium squamuloso-pilosum Ching

Korean name: Huin-geum-teol-go-sa-ri (흰금털고사리) (Figs. 1, 2).

Herbs, mostly rupestral, 12–30 tall. Rhizomes shortly creeping, 1–2 mm in diameter, densely scaly; scales linear to narrowly lanceolate, 10–17 × 1.0×1.7 mm, reddish brown, lustrous, membranous. Stipes 5–23 cm long, stramineous, densely scaly on swollen base, densely grayish white hairy, rarely mixed with curly, linear scales at upward. Lamina 3–4 pinnatifid, ovate-oblong, base cordate, apex acuminate, herbaceous, 8–15 × ca. 7–12 cm, densely white long hairy on rachis and costae, sometimes mixed with glandular hairs and curly, linear, reddish brown scales. Pinnae 8–12 pairs, lower pairs 2–4 cm apart, basal pair almost opposite and largest, oblong lanceolate, apex shortly acuminate, 2–3 pinnatifid, base cordate, 5–8 × 2.5–3.5 cm, basal pinnae shortly stalked. Pinnules 7–9 pairs, alternate, anadromous, shortly stalked, upper ones smaller, apex round or obtuse, margins serrate. Veins free, simple, ending at margin. Sori orbicular, 1–4 per segment, located on the middle of veinlets. Indusia reniform, persistent, almost entire or somewhat serrate at margin, densely covered with hairs.

Habitat: In rocks of limestone regions within forests.

Distribution: Yeongwol-gun, Gangwon-do, Korea.

Specimens examined: KOREA. Gangwon-do: Yeongwol-gun, Hanbando-myeon, elev. 240 m, 24 Sep 2016, C.S. Lee & K. Lee 16092401 (EWH [4 sheets], KH [3 sheets], KB [3 sheets]; 28 Oct 2013, K. Lee & M.K. Lee 13102801 (KH [1 sheet]).

Taxonomic notes: The newly reported taxon in Korea, Hypodematium squamuloso-pilosum is known as an endemic in China (Zhang and Iwatski, 2013) but was found first in Gangwon-do in Korea.

The new local name ‘Huin-geum-teol-go-sa-ri’ was given based on its having throughout long white hairy. It was firstly found with Cornus walteri, Fraxinus rhynchophylla, Celtis koraiensis, Lespedeza maximowiczii, Ulmus davidiana var. japonica, Juniperus rigida, Aster scaber, and Commelina communis in a forest in Hanbando-myeon, Yeongwol-gun, Gangwon-do.

This taxon is distinguished from H. glanduloso-pilosum (Tagawa) Ohwi reported as one species of Hypodematium in Korea based on scales in rhizome and stipe base linear to narrowly lanceolate, white long hairs throughout leaves, rarely reddish brown curly linear scales on stipe, and basal pinna oblong-lanceolate.

The chromosome numbers of H. squamuloso-pilosum and H. hirsutum have the same type as n = 41 (41 II) based on cytotaxonomic study by Wang et al. (2014). This taxon firstly described from Korea was most similar with H. hirsutum distributed in China, Bhutan, India, Myanmar, and Nepal based on rhizome, scale shape and size, sori position, and hairs in indusia (Iwatsuki, 1992, 1995; Wang et al., 2010; Zhang and Iwatsuki, 2013) (Table 1). Hypodematium fordii distributed in China and Japan was also similar with H. squamuloso-pilosum, but the former has different characters from the latter based on almost glabrous upward in stipe, densely glandular hairs in lamina, triangular ovate basal pinna, and sparsely glandular hairs in indusia (Table 1).

Furthermore, it was distinguished from other taxa of the genus Hypodematium the distinct characters such as densely long hairs throughout the leaf and sparsely with glandular hairs and reddish brown curly linear scales, and basal pinna oblong lanceolate (Table 1).