L.H.Is.: summit plateau of Mt Gower, P.S.Green 1655 (A); loc. id., P.S.Green 1996 (K); 600 m N of tableland on W side of Mt Lidgbird, J.Pickard 3632 (K, NSW).
norfolkianum(Heward) Maiden Proc. Linn. Soc. New South Wales 28: 732(1904)
Lomaria norfolkiana Heward, London J. Bot. 1: 122 (1842); Blechnum lanceolatum var. norfolkianum (Heward) Laing, Trans. & Proc. New Zealand Inst. 47: 13 (1915).T: Norfolk Island, A.Cunningham 34; holo: K. Named after Norfolk Is.
Lomaria acuminata Baker in W.J.Hooker & J.G.Baker, Syn. Fil. 2nd edn, 481 (1874), nom. illeg. non Desv. (1811), nec C.Presl (1825); Spicanta acuminata (Baker) Kuntze, Revis. Gen. 2: 821 (1891), nom. illeg.; Blechnum acuminatum (Baker) Maiden, op. cit. 733 (1904) nom. illeg. non Fée (1852), nec Sturm (1853).T: Norfolk Island, [Milne 14]; holo: K.
[Lomaria lanceolata auct. non (R.Br.) Spreng.: W.J.Hooker, Icon. Pl. 5: sub t. 429 (1842), p.p.]
[Blechnum lanceolatum auct. non (R.Br.) Sturm: J.H.Maiden, op. cit. 732]
[Blechnum nudum auct. non (Labill.) Mett. ex Luerss.: J.H.Willis, Handb. Pl. Victoria 1: 43 (1962), p.p.]
Terrestrial fern. Rhizome short, erect; apical scales 3–4 mm long, long-pointed, dark brown. Fronds dimorphic, erect, not geniculate, glabrous, clustered; stipe 10–35 cm long. Lamina of sterile fronds deeply pinnatifid, overall outline elliptic, 30–80 cm long, 4.5–20 cm broad; pinnae 15–30 pairs (excluding the greatly diminished basal pairs), slightly dentate, especially towards apex, long-acute, the longest 2.5–10 cm long, 0.7–1.7 cm broad; median pinnae narrowing in their upper half; basal pinnae very gradually reduced for c. 1/3 length of lamina, ±at right angles to the rachis, apices obtuse; major sterile pinnae narrowing in their upper half; veins often forking once near midrib. Lamina of fertile fronds pinnate, with 25–35 pairs of linear pinnae.
Norfolk Island Water Fern.
Norfolk Is. Not common; occurs on Mt Bates. Also known from the Kermadec Is., Vanuatu, Samoa and the Society Is.
Found in valleys in the middle and upper slopes of Mt Bates.
N.Is.: E slopes of Mt Bates, R.D.Hoogland 11195 (CANB, K, NSW); between Palm Glen and Red Rd, M.Lazarides 8085 (CANB, K, NSW); loc. id., R.J.Chinnock 5953 (AD, K); S slopes of Mt Bates, P.S.Green 1866 (K); s. loc., A.Cunningham 34 & 56 (K).
The Kermadec Island plants are perhaps a little less robust and the margins of the pinna lobes slightly more dentate than those on Norfolk Island. This species is very close to B. chambersii Tindale (B. lanceolatum (R.Br.) Sturm) of eastern Australia and B. aggregatum (Colenso) Tindale of New Zealand.
One collection in MEL from Lord Howe Is. (the south-eastern side of Mt Lidgbird) made on 26 Nov. 1962 by A.C.Beauglehole (A.C.Beauglehole 5398) may be this species. It differs from the Norfolk Is. plant only by being almost completely pinnate (the base of the pinnae are scarcely joined even by a 1 mm wide continuation of the lamina) and the tips of the pinnae lack even very slight serrations.
[Lomaria attenuata auct. non (Sw.) Willd.: G.Bentham, Fl. Austral. 7: 736 (1878), et sensu aliorum]
[Blechnum attenuatum auct. non (Sw.) Mett.: W.W.Watts, Proc. Linn. Soc. New South Wales 37: 397 (1913); W.R.B.Oliver, Trans. & Proc. New Zealand Inst. 49: 116 (1917)]
Illustration: C.J.Goudey, Austral. Fern J. 1:  t. 9 (1984).
Climbing epiphyte fern. Rhizome long, covered with dense, narrowly lanceolate scales; scales c. 1.5 cm long, with a long fine apex. Fronds dimorphic, 0.5–2 cm apart on rhizome; stipe 5–10 cm long, with a few scattered, narrow scales. Sterile fronds erect, not geniculate; lamina pinnate, overall outline narrowly lanceolate, 30–50 cm or more long, 5–12 cm broad, glabrous or a few narrow scales beside midrib beneath; base with gradually reduced pinnae; pinnae 30–40 pairs, borne at an angle of 45°–60° to midrib, not overlapping, narrowly elongate-triangular, sometimes somewhat falcate, (2.5–) 3–7 cm long, 0.5–1 cm broad at base, diminishing gradually to a long-acute apex, with bases entire; veins distinct below, usually forked once. Lamina of fertile fronds pinnate; pinnae 40–50 pairs, narrowly linear, 4–10 cm long.
Lord Howe Is. Frequent on the summits of Mts Gower and Lidgbird. Also known from New Caledonia.