M.Is.: E side of plateau towards Nuggets, 23 Jan. 1949, N.R.Laird (HO); 500 m NW of Island Lake, R.D.Seppelt 11903 (HO); western slopes of Mt Ifould, R.D.Seppelt 12577 (HO); 500 m E of Mt Gwynn, R.D.Seppelt 12600 (HO, MEL); Boot Hill, NE side of summit, R.D.Seppelt 12725 (HO).
Although most specimens from the island are very uniform morphologically, one aberrant record is known (Bauer Bay, R.D.Seppelt 11701 (HO)). This consists of soft thin sterile fronds, most of which are longer than normal, more or less linear, some acute, and many with sparse red-brown multi-cellular hairs on the margins and faces of the lamina. These are believed to be young shade forms, probably from deep bryophyte cushions, which have retained a juvenile form and indumentum.
Terrestrial, rarely epiphytic ferns; rhizome erect (sometimes forming a trunk), creeping or scandent, scaly towards apex. Fronds usually in a crown, sometimes scattered along rhizome, often coarsely textured, simple to bipinnate but usually pinnate with lobed pinnae; lateral pinnae usually subequal; basal lateral pinnae sometimes greatly reduced; apical pinna triangular and deeply lobed near base. Fertile frond usually similar to sterile ones. Sori on the veins, usually ±circular, indusiate or not; indusium reniform when present, attached at one side.
A large family of almost 1000 species in c. 30 genera; 2 genera on Christmas Is. Distributed throughout the tropics, especially in wetter forest ares, with a few species in temperate regions.
KEY TO GENERA
Fronds with c. 6–10 pairs of greatly reduced basal pinnae; pinnae lobed 1/3–1/2 way to midvein, with several pairs of veinlets anastomosing below pinna lobe sinuses; sori on undersurface of lamina of pinna lobes, not submarginal
Fronds lacking a series of greatly reduced basal pinnae; pinnae lobed 2/3–3/4 towards midvein, with a single pair of veinlets anastomosing below pinna lobe sinuses; sori submarginal
PneumatopterisNakai Bot. Mag. Tokyo 47: 179(1933) from the Greek pneuma (air, breath) and pteris (a fern), in reference to the breathing pores (aerophores) at the base of the pinnae
Type: P. callosa (Blume) Nakai
Terrestrial ferns; rhizome short, erect or decumbent, rarely creeping; scales on stipe base and rhizome broad, thin, with a few marginal hairs; fronds in a crown. Stipe usually grooved; vascular strands 2 at base, linear in T.S. Fronds usually large, arching, not articulate, pinnate, the pinnae becoming gradually reduced towards the apex, and usually abruptly so towards base, often with swollen aerophores on rachis at base of pinna; pinnae lobed; veins occasionally all free, usually the basal veins of the pinna lobes anastomosing. Sori small, circular, in paired rows in the pinna lobes; indusium reniform, thin; paraphyses absent.
A genus of c. 80 species, distributed throughout the Old World tropics, from Africa to the Pacific islands, Australia and New Zealand, with greatest diversity in Malesia; 1 species on Christmas Is. They mainly occur near streams in tropical forest, and a few species are confined to limestone.
A large, terrestrial fern; rhizome erect; scales broad, c. 5 mm long, thin; fronds in a crown. Stipe 10–30 mm long, grooved above. Fronds c. 80–120 cm long, bipinnatifid, with aerophores at base of pinnae, the terminal pinna similar to lower pinnae, the frond base with c. 6–10 pairs of greatly reduced pinnae; pinnae numerous, sessile, to c. 15–25 cm long, acuminate, shallowly lobed 1/3–1/2 way to midvein, obtuse at base, ±glabrous; lobes truncate, slightly toothed; several pairs of veinlets anastomosing below pinna lobe sinuses. Sori circular, in rows either side of midvein of pinna lobes; indusium small, reniform.
Christmas Is., collected by C.W.Andrews and H.N.Ridley in the region of Waterfall, and may occur elsewhere on the island where there is water near the surface. Occurs from India and southern China, through Indo-China and western Malesia, to the Philippines, the Lesser Sunda Islands and the Mariana Islands.
The young fronds are covered in mucilage, probably giving protection from dessication. The aerophores protrude through this, allowing the developing frond to respire.
AmphineuronHolttum Blumea 19: 45(1971) from the Greek amphi (of two kinds or places) and neuron (a nerve, vein), in reference to the varied venation of the fronds
Type: A. opulentum (Kaulf.) Holttum
Terrestrial ferns; rhizome erect to creeping; scales narrow, setiferous, on the young fronds and stipe base; fronds in a crown or scattered along rhizome. Stipe grooved; vascular strands 2 at base. Fronds often large, arching, not articulate, pinnate, the pinnae becoming gradually reduced towards apex, the basal pinnae only slighty reduced, with elliptic aerophores on rachis at base of pinna; pinnae lobed, usually glandular-hairy. Veins all free, or the basal veins of the pinna lobes anastomosing or connivent at sinuses. Sori small, circular, in paired rows in pinna lobes; indusium reniform, glandular or hairy.
The c. 12 species in this genus are native to the Old World tropics, from eastern Africa and SE Asia, through Malesia to Australia (Qld) and the Pacific islands; 1 species on Christmas Is. They occur in rather open sites, particularly near streams and often in areas with seasonal climate, sometimes preferring limestone.
Aspidium opulentum Kaulf., Enum. Filic. 238 (1824).T: Guam, A. von Chamisso; n.v. Epithet from the Latin opulentus (sumptuous, wealthy), perhaps in reference to the lush growth habit of this fern.
Illustrations: D.L.Jones & S.C.Clemesha, Austral. Ferns & Fern Allies 2nd edn, 75, fig. 54 (1981); R.E.Holttum, Fl. Males. ser. II, 1: 546, fig. 19 B & C (1982).
A large, terrestrial fern; rhizome creeping; scales c. 10 mm long, narrow; fronds closely spaced. Stipe c. 35–60 cm long, grooved above. Fronds c. 50–80 cm long, bipinnatisect, with aerophores at base of pinna, the terminal pinna subsimilar to the lower pinnae, the lowest pinnae sometimes reduced; pinnae numerous, sessile or short-stalked (to c. 1 mm), to c. 25–30 cm long, acuminate, deeply lobed 2/3–3/4 towards midvein, obtuse at base, shortly hairy especially on veins, with minute glands on the veins beneath; lobes acute, curved, ±entire, with tiny yellow particles on undersurface; 1 pair of veinlets anastomosing below pinna lobe sinuses. Sori circular, submarginal, mostly confined to pinna lobes; indusium small, reniform.
Christmas Is. It appears to be a recent introduction, occurring along tracks and in the more open areas of rainforest on the plateau. A widely distributed species in the Old World, occurring from eastern Africa, the Seychelles and southern India, through Indo-China, Malesia to Australia (Qld) and the Pacific islands (to Tahiti and Marquesas). It has become naturalised in a few New World localities.
Ch.Is.: track side, N of Aldrich Hill, D.J. & B.P.Du Puy CI21 (CBG, K).
This species closely resembles Pneumatopteris truncata (Poir.) Holttum, but can be distinguished by its creeping rhizome, lack of a series of highly reduced pinnae at the frond base, more deeply lobed pinnae, acute pinna lobes, hairy veins, fewer anastomosing veinlets, and its submarginal sori which are mostly confined to the pinna lobes. On Christmas Is. occurs mainly alongside Nephrolepis biserrata which it resembles in habit, but has deeply lobed rather than entire pinnae.
Rhizomes long-creeping, underground, bearing hairs; stipes often distant. Fronds large, much-divided, usually with multicellular hairs on the rachis and usually the lamina; veins free or anastomosing. Sori marginal or submarginal, terminal on veins, indusiate; indusium continuous from margin of lamina or pouch shaped, or sorus protected by a 'cup' formed from the fusion of the indusium with a lobe of the leaf margin.
A mainly tropical family, variously considered to contain between 7 and 17 genera; 1 genus on Christmas Is.
MicrolepiaC.Presl Tent. Pterid. 124, t. 4(1836), nom. cons. from the Greek mikros (small) and lepis (a scale), in reference to the small, scale-like indusia
Type: M. polypodioides (Sw.) C.Presl
Terrestrial ferns; rhizome creeping, shortly hairy; fronds scattered along rhizome, in 2 rows. Stipe grooved; vascular stand U-shaped in section. Fronds suberect to arching, usually 2–4-pinnate, rarely simply pinnate, with an occasionally sparse indumentum of short hairs; pinnae becoming gradually reduced towards apex; lobes usually toothed to pinnatifid, the basal lobe enlarged; rachis and costae shallowly grooved; veins all free. Sori subcircular, submarginal, often near base of sinuses, terminal on veins; indusia attached at base and sides, cup-shaped, opening towards margin, the surface hairy.
The c. 45–50 species in this genus are mainly native to SE Asia; 1 species, M. speluncae, has a pantropical distribution including Africa, Australia and the New World. This is the only species present on Christmas Is. and is probably native there. The species mainly occur in moist to wet forests.
W.A.Sledge, Microlepia speluncae (L.) Moore, M. trapeziformis (Roxb.) Kuhn and M. firma Mett. in Kuhn, Kew Bull. 11: 523–531 (1956); R.E.Holttum, Fl. Malaya (Ferns) 2nd edn, 2: 306–316 (1968); M.Tagawa & K.Iwatsuki, Fl. Thailand 3: 112–124 (1979); D.L.Jones & S.C.Clemesha, Austral. Ferns & Fern Allies 2nd edn, 168–169 (1981); R.M.Tryon & A.F.Tryon, Ferns & Allied Pl. 373–377 (1982).
Polypodium speluncae L., Sp. Pl. 2: 1093 (1753); Davallia speluncae (L.) Baker in W.J.Hooker & J.G.Baker, Syn. Fil. 100 (1868).T: Ceylon [Sri Lanka], Herb. P.Hermann vol. 3, fol. 41, no. 384; lecto: BM, fide W.A.Sledge, Bot. J. Linn. Soc. 84: 25 (1982). Epithet from the Latin spelunca (a cave), in reference either to the indusium shape or to the habitat.
Large, terrestrial fern; rhizome creeping, dark brown, the young parts shortly hairy, with few, closely spaced fronds. Stipe c. 30–75 cm long, grooved, sparsely shortly hairy, purple-brown. Fronds arching, c. 60–90 cm long, deeply tripinnatisect to tripinnate, finely hairy, thinly and softly herbaceous; pinnae largest towards base, to 20–35 cm long; pinnules shortly stalked, narrowly triangular, deeply lobed, the basal lobes distinctly enlarged and often ±stalked; lobes oblong, to 8–15 mm long, rounded, deeply incised to shallowly toothed, decurrent, sparsely hairy above and beneath; veins all free. Sori ±circular, submarginal near sinuses of lobe teeth; indusium cup-shaped, opening outwards.
Christmas Is. Confined to the upper terraces and plateau, among other ferns on the sides of tracks through the primary rainforest, and also in damp situations in marginal forest, especially in areas of basaltic rock. A pantropical species, perhaps introduced to the New World. It occurs in Australia (W.A., Qld).
Ch.Is.: Flying Fish Cove, H.N.Ridley 187 (K); Sydneys Dale, D.A.Powell 4461 (K); Headridge Hill, B.Molesworth Allen P5 (K); Stewart Hill, D.J. & B.P.Du Puy CI36 (CBG, K); SW of Hanitch Hill, D.J. & B.P.Du Puy CI70 (CBG, K).
This is a very variable species, the degree of division increasing in older and larger specimens. It is also variable in the hairiness of the fronds, and several varieties and even separate species have been distinguished. The specimens from Christmas Is. have hairs on the lamina as well as on the veins, corresponding most closely to var. pubescens (Hook.) Sledge (sensu W.A.Sledge, Kew Bull. 11: 525, 1956) and var. villosissima C.Chr. (sensu R.E.Holttum, Fl. Malaya (Ferns) 2nd edn, 2: 315, 1968).
Terrestrial or epiphytic ferns, with creeping or erect rhizomes covered with dark brown, latticed scales. Fronds simple or compound; veins usually free. Sori elongate, along one side of the veins with a narrow, linear indusium.
A cosmopolitan family of 1 large genus (Asplenium) and about 7 smaller ones; 1 genus on Christmas Is.
AspleniumL. Sp. Pl. 2: 1073(1753) Gen. Pl. 5th edn, 485 (1754); from the Greek a (not) and splen (a spleen), in reference to the former use of some European species as a remedy for disorders of the spleen. Dioscorides used the name 'asplenon' for these ferns
Type: A. marinum L.
Epiphytic, lithophytic or terrestrial ferns; rhizome erect or creeping; scales dense, small, minutely latticed, dark brown, on rhizome and stipe base; fronds scattered or in a crown. Stipe grooved, with 2 vascular strands. Fronds erect to pendulous, simple to 4-pinnatified, often with vegetative buds, not articulate; veins usually forked, free, rarely uniting upwards into a submarginal vein. Sori elongate to linear, along one side of vein; indusium narrow, attached along vein, usually opening towards midrib of frond segment.
This is one of the largest fern genera, with c. 600–650 species distributed world-wide, from the arctic to the tropics; 3 species on Christmas Is. They most frequently occur in moist forest, as lithophytes or epiphytes. They include several attractive species which are popular in cultivation. Some species are exceptionally variable in habit, and many cultivars have been selected.
A large, epiphytic or occasionally lithophytic fern; rhizome erect, stout, scaly; scales narrow c. 1–2 cm long, hair-like towards apex, latticed, dark brown, glossy; fronds in a crown. Stipe 2–5 cm long, grooved above, black, scaly at base. Fronds erect to spreading, forming a rosette, simple, linear-elliptic, narrowed to base, entire, acute, to 100–150 cm long, c. 15–25 cm wide, ±glabrous, rather coriaceous; midvein raised above; lateral veins numerous, forked, joined towards apex by a submarginal vein. Sori narrow, linear, in apical half of frond, on lateral veins; indusium linear.
Bird's Nest Fern.
Christmas Is. Abundant in the rainforest, especially on the plateau and upper terraces, where it can form very large specimens. It is most frequent in the canopy and on the emergent trees Syzygium nervosum, Planchonella nitida and Hernandia ovigera, and is occasionally found as a lithophyte on sheltered limestone rocks and pinnacles in the forest. A common species in the Old World Tropics, from India and southern China through Indo-China, Malesia (including the Malay islands) and Australia (Qld) to Hawaii.
Ch.Is.: northern plateau, D.A.Powell 115 (K); walk to West White Beach, R.Shivas 921 (PERTH).
This species traps leaf litter by producing erect fronds which later bend outwards, trapping any litter at their base. The root ball becomes large and is capable of holding large amounts of water. This root ball is a habitat utilised by other epiphytic ferns including Vittaria elongata, Asplenium polyodon and Ophioglossum pendulum.
polyodonG.Forst. Prodr. 80(1786)
T: none cited; n.v. Epithet from the Greek polus (many) and odons (a tooth), in reference to the toothed pinnae.