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Australian ferns & fern allies |
Erect ferns of shallow waters and swamps; rhizome short, fleshy, radial, with many vascular strands. Fronds with a long spongy stipe, with numerous longitudinal air canals and many vascular bundles in a single ring, the lamina glabrous, dimorphic, the sterile frond 2 - 3-pinnatifid with broad, thin spreading segments, the fertile fronds erect with narrower, linear, coarser segments; the venation regularly reticulate without free included veinlets. Sporangia solitary, scattered along the veins of the contracted fertile segments, protected by the reflexed edge of the lamina; annulus broad and irregular, or lacking; spores trilete.
A pantropical family of a single genus with 4 species. Ceratopteris thalictroides is the sole species in Papuasia.
Erect aquatic or subaquatic ferns of moderate size. Rhizome short, fleshy, horizontal and ascending to erect, loosely rooted in the mud or +/- floating, radial, dictyostelic with numberous meristeles and medullary strands, young parts bearing thin, ovate, +/- cordate, clathrate scales. Fronds stipitate, the stipes fleshy, with numberous longitudinal air canals, abaxially rounded and ribbed, adaxially flattened, vascualr bundles in a peripheral ring, one with each rib and several to the adaxial side, and several smaller medullary strands; lamina dimorphic, sterile fronds +/- spreading, 2 - 3-pinnatifid with broad membranous lobes, venation reticulate without included free veinlets, often with proliferous buds in the axils; fertile fronds erect, longer, narrower and more divided than the sterile, the lobes strongly recurved to completely cover the adiaxial surface, venation longitudinal, branching at the bases of the lobes. Sporangia solititary, scattered along the veins, exindusiate but protected by the continuous reflexed margin of the lamina, large, short-stalked, annulus broad, irregular, of 30 - 70 thickened cells, or lacking, containing 16 to 32 spores. Spores large, trilete, ribbed with irregular long meshes.
Distribution: A widespread genus of 4 species in the humid tropics with a single species in Papuasia.
Copeland, E.B. 1942. Edible ferns. Amer. Fern J. 32: 121 - 126, pl.
Croft, J.R. 1985. Ferns and Fern Allies, in Leach, G.J. & Osborne, P.L. 1985. Freshwater Plants of Papua New Guinea. 33 - 74, f. 6 - 13, pl. 5 - 7.
Donsellar, J. van 1969. On the distribution and ecology of Ceratopteris in Surinam. Amer. Fern J. 59: 3 - 8.
Fosberg, F.R. 1958. Notes on Micronesian Pteridophyta, II. Amer. Fern J. 48: 35 - 39. (Ceratopteris)
Johns, R.J. & Bellamy, A. 1979. Ferns and fern allies of Papua New Guinea. P.N.G. Office of Forests. (incl. Parkeriaceae)
Johnson, A. 1961. The genus Ceratopteris in Malaya. Gard. Bull. Sing. 18: 76 - 81.
Lloyd, R.M. 1972. Species delimitation in the genus Ceratopteris (Parkeriaceae). Amer. J. Bot. 59: 676.
Lloyd, R.M. 1973. Sexual and vegetative reproduction in Hawaiian Ceratopteris thalictroides. Amer. Fern J. 63: 12 - 18.
Lloyd, R.M. 1974. Systematics of the genus Ceratopteris Brongn. (Parkeriaceae) II. Taxonomy. Brittonia 26: 139 - 160, f. 1 - 9.
A single species in Papuasia:
Plants usually rooted in mud, very variable in size and appearance, scales on rhizome peltate, thin , translucent, pale brown, (under a lens clear with dark cell walls) stipes 3 - 15 mm diameter in mature plants, spongy and air filled, sterile fronds pale green, thin, flaccid and spreading, 4 - 60 cm long, including a stipe c. half this length, fertile fronds pale green, to brown when over mature, firm, held erect, 15 - 100 cm or more long, including stipe to 40 cm long, proliferous or dormant buds with overlapping dark scales sometimes present in the axils of fertile pinnae (twice seen), sterile axes obviously winged, pinnae basically broad-ovate or deltoid with a few blunt lobes, sometimes more deeply incised, the segments 2 - 15 x 10 - 30 mm, fertile segments linear, 1 - 2 x 10 - 80 mm.
Habitat: Swampy areas, swamp forests, sago (Metroxylon) swamps, marshes, natural and mand-made ponds, mostly in stagnant water bodies or in still pockets along slow flowing rivers, full sun to moderate shade, from sea level to 1300 m, but mostly less than 500 m altitude. Sometimes massed on or around logs or other floating vegetation, once recorded in a fresh-water mangrove (Sonneratia) growing amoun the finger-like pneumatophores. In some areas Ceratopteris exhibits a degree of seasonality, reaching maturity and shedding spores during the dry season; plants have lost nearly all sterile fronds by this stage.
Distribution: Throughout the lowland tropics of the Old World. In Papuasia it has been recorded from nearly all lowland regions.
Notes: In some areas (Sepik, Northern Province) the fronds of this species are cooked as a green vegetable. In Micronesia it is eaten as a salad (Fosberg 1958). It is also eaten in the Philippines (Copeland 1942). In the Sepik it is used as a personal decoration.
