89. Asplenium ritoense Hayata, Icon. Pl. Formosan. 4: 226. 1914.
骨碎补铁角蕨 gu sui bu tie jiao jue
?Asplenium dareoideum (Mettenius) Makino; A. davallioides Hooker (1857), not Tausch (1839); ?Humata dareoidea Mettenius.
Plants 20-40 cm tall. Rhizome erect, short, apex scaly; scales dark brown, narrowly triangular, margin fimbriate. Fronds caespitose, dimorphic, sterile fronds reduced in size and division; stipe green, base dull purplish or green, 7-22 cm, base scaly, upward with hairlike scales or subglabrous, sulcate and with supravascular ridge and narrow lateral wings on adaxial side; lamina triangular to broadly triangular-ovate, 11-17 × 5-7 cm, apex acuminate or caudate, tripinnate-pinnatifid; pinnae 10-12 pairs, alternate, stalked, basal pair largest, narrowly triangular, 3-7.5 × 1.6-3 cm, base broadly cuneate, nearly symmetrical, 2-pinnate, apex acute-acuminate; pinnules 5-9 pairs, anadromous, acroscopic pinnules larger than basiscopic, ovate-triangular, 1-2.5 × 0.7-1.3 cm, base cuneate and decurrent on pinnule stalk, pinnate, apex subacute; ultimate segments 4 or 5 pairs, basal acroscopic segment largest and 5-8 × 3-6 mm, 2- or 3-lobate, ultimate segments oblong, up to 2 mm, furcate or simple, apex subobtuse to mucronate or acute. Costa and veins with raised supravascular ridge on adaxial side, 1 vein per segment, not reaching margin. Frond subfleshy when living, thin, green when dry; rachis raised on both sides, narrowly winged. Sori 1 per segment, distal on subtending vein and ± as long as subtending segment but not reaching its apex, oval to linear, 2-4 mm; indusia yellowish brown, semi-elliptic, membranous, margin with reddish glands, often rolling back at maturity, opening toward its costule and margin. Plants tetraploid: 2n = 144.
On rocks in lowland forests; 100-1900 m. Fujian, Guangdong, Guizhou, Hainan, Jiangxi, Taiwan, Zhejiang [Japan, Korea].
We were unable to trace Metteniuss type specimen of Humata dareoidea in Berlin (B). If it belongs to Asplenium ritoense, then Makinos combination is to be used. Asplenium ×shikokianum Makino, the hybrid between A. ritoense and octoploid A. wrightii, is not uncommon where the parents grow together (e.g., Guizhou, Taiwan).