台灣植物誌 第二版 Flora of Taiwan, 2nd edition Vol. 1
29. ASPLENIACEAE 鐵角蕨科
SHIEH, WANG-CHUENG, DEVOL, CHARLES E. and KUO, CHEN-MENG
Terrestrial, petrophilous or epiphytic ferns of a wide variety of forms; rhizomes dictyostelic, creeping or erect; scales usually clathrate, narrowly lanceolate, dark brown to black. Fronds simple, pinnate to decompound; stipes not articulate to rhizome, with two vascular strands at base of stipe, uniting to form an Ｘ shaped strand in upper stipe; venation usually free and forking. Sori linear, borne on side of a veinlet; indusia linear, narrow.
Containing the one large genus Asplenium and about ten small genera; only one genus in Taiwan.
1. ASPLENIUM L. 鐵角蕨屬
Rhizome creeping, or short and erect; mostly terrestrial or growing on rocks, some epiphytic on tree trunks; scales clathrate, dark brown to black; margins of bases of pinnac or pinnules continuous with rachis groove. Fronds simple, longitudinally cleft, trifoliate, or pinnate to decompound, sometimes proliferous at apex; venation free except in a few species where the tips of the veins unite to form an intramarginal vein. Sori linear, borne on side of a vein; indusia linear, narrow, usually opening towards the midrib.
A genus of about 700 species, 35 in Taiwan.
KEY TO SPECIES
1. Fronds simple, entire or nearly so; usually widest near middle, tapering to either end; stipes tufted.
2. Large epiphytes, fronds 1-2 m long, 10 cm or more wide; apices of the parallel veins uniting to form an intramarginal line.
3. Sori extending 2/3 way from costa to margin; basal scales nearly entire… 3. A. antiquum
3. Sori extending about 1/2 way from costa to margin; margins of scales bearing long hair-like projections… 15. A. nidus
2. Smaller terrestrial ferns, lamina to 30 cm long, 1-3 cm wide; veins free.
4. Stipes 10-18 cm long… 10. A formosae
4. Stipes very short.
5. Undersurface of lamina without scales… 8. A. ensiforme
5. Undersurface of lamina sparsely covered with small scales… 11. A. griffithianum
1. Fronds variously cleft or lobed to decompound.
6. Fronds longitudinally cleft into narrowly linear segments… 24. A. septentrionale
6. Fronds not longitudinally cleft.
7. Lamina pinnate (pinnae serrate-crenate or not cut more than 1/4 way to costa).
8. Lamina ending in a distinct terminal pinna.
9. Pinnae entire or undulate… 10. A. formosae
9. Pinnae serrate.
10. Terminal pinna with one or 2 projecting basal lobes; margins finely serrulate… 1. A. adiantoides
10. Terminal pinna linear or narrowly lanceolate; margins coarsely toothed… 25. A. serricula
8. Lamina with a pinnatifid apex or ending in very small gradually shortened pinnae.
11. Rhizome long creeping; texture of lamina very thin.
12. Sori confined to the marginal teeth… 6. A. cheilosorum
12. Sori not marginal.