台南铁角蕨 tai nan tie jiao jue

Asplenium mertensianum Kunze.

Plants 50-90 cm tall. Rhizome shortly creeping to erect, scaly. Stipe terete to semiterete, sulcate toward rachis, ca. 40 cm, base dull brown or green, with pale brown, narrowly triangular scales, 8-10 × 1.5-2 mm with basal margin fimbriate. Lamina ovate-oblong, 40-50 × 22-25 cm, apex acute, 3-pinnate or 4-pinnatifid; pinnae 10-15 pairs, lower pinnae opposite or subopposite, close to each other, stalk 0.6-1 cm, upper pinnae alternate, 1-3 pairs of basal pinnae not reduced, ovate-triangular, 12-17 × 3-7 cm, base broadly cuneate, 2-pinnate, apex acute; pinnules 9-11 pairs, anadromous, stalked, basal pair longest, narrowly triangular to ovate, 5-7 × 2-2.5 cm, base cuneate, pinnate, apex subacute; ultimate segments alternate, basal acroscopic segment largest, oblong, 3-4 × 1-5 mm, bifurcate or simple, apex subacute to obtuse. Veins raised on adaxial surface, 1 per ultimate segment, not reaching margin. Fronds fleshy, green, with small hastate-stellate scales on abaxial surface; rachis and costa green, sulcate adaxially, with narrow lateral wings. Sori 1 per pinnule, median on subtending veinlet, oval to linear, 3-5 mm; indusia grayish, oval to broadly linear, membranous, entire, opening toward costule and margin, persistent. Plants agamosporous, octoploid: 2n = 286.

Taiwan [Japan (Bonin Islands, Ryukyu Islands)].

Asplenium trigonopterum has not been found recently and was not included in modern floras of Taiwan (De Vol & Kuo, Fl. Taiwan 1: 1-562. 1975; Shieh et al., Fl. Taiwan, ed. 2, 1-648. 1994; Knapp, Ferns Fern Allies Taiwan, 1-1052. 2011), and its actual occurrence on the island requires confirmation.

Asplenium fangii Ching (Bull. Fan Mem. Inst. Biol., n.s., 1: 276. 1949), described from Sichuan. The type in PE(!) represents a species of Diplazium s.l.

Asplenium pekinense Hance var. nanum Christ (Nuovo Giorn. Bot. Ital., n.s., 17(2): 225. 1910), described from Hubei. Type (Silvestri 7, FI) not seen, probably a dwarf form of A. pekinense.

Asplenium pseudofalcatum Hillebrand f. obtusatum Rosenstock (Hedwigia 56: 334. 1915), described from Taiwan. Type (Faurie 455bis) not seen, probably a form of A. cuneatiforme.

Asplenium pseudofalcatum Hillebrand var. subintegrum Rosenstock (Hedwigia 56: 334. 1915), described from Taiwan. The isotype in MICH (photo!) is probably A. cuneatiforme but is close to A. lobulatum Mettenius ex Kuhn. The relationship of these taxa needs more study.

Asplenium wilfordii Mettenius ex Kuhn var. densum Rosenstock (Hedwigia 56: 334. 1915), described from Taiwan. The isotype in NY (photo!) resembles A. austrochinense, but this taxon should be confirmed for Taiwan.

Neottopteris longistipitata R. H. Miao (Acta Sci. Nat. Univ. 1: 99. 1980), described from Hainan.