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Pteridophytes

The ferns and their allies.

Plants characterised by a very distinct alternation of generations with independent inconspicuous and sort-lived gametophyte (sexual) and conspicuous and dominant sporophyte (asexual) stages. Sporophyte vascular herbs, mostly terrestrial, rupestral or epiphytic, sometime floating, submerged or emergent aquatic, mostly soft or delicate, sometimes harsh or stout, rarely arborescent. Stem often rhizomatous, radial or dorsiventral, erect, prostrate, climbing, or subterranean; often with scales and/or hairs; mostly with true roots; stele simple to complex. Leaves either small, simple and bract-like or linear with a simple vein, straight in bud, or a broad frond with branched or divided veins, simple to several times pinnately divided, conduplicate or mostly circinnate in bud; bearing sporangia. Leaf stalk or stipe mostly present and mostly lacking stipules. Sporangia moslty grouped in sori or fused in synangia, or solitary in axils or sporophylls which may be grouped into strobili; sori naked or often protected by an indusium. Spores monolete or trilete; germinating to form an avascular prothallus (gametophyte stage) bearing male antheridia and/or female archegonia; gamete transfer and fertilization by water, producing a new plant which obliterates the prothalus (sporophyte stage).

Distribtion

A large group of ancient or primitive land plants with worldwide distribution, all continents except Antarctica and most islands, favouring moist temperate and tropical regions, they can be found in all but the most frigid and most arid environments. Free water is required for fertilization and the production of a new generation of plants. There are no marine species.

Notes

The 'Pteridophyta' is generally considered to be a biologically unnatural group but the use of the term persists, largely out of convenience and the need for a handle for the 'ferns and related plants'.

The pteridophytes are a collection of several major groups at the division or class level that rank alongside the Bryophyta (mosses and liverworts) and the Spermatophyta (seed-plants). There are 4 such groups, one of which are the true ferns, the remainder the fern allies:

In this work, for purely practical purposes, these higher divisions are largely ignored.

Key to the major groups

1 Leaves microphyllous, simple or once-divided, with a single vein and no petiole; sporangia solitary or in 2 - 3-celled synangia, axillary or on peltate sporophylls (fern allies)... ...2
Leaves megaphyllous, variously divided with several to many veins; sporangia mostly in clusters of several to many, abaxial or on special outgrowth of the lamina (true ferns - Polypodiophyta )... true ferns
2 2 - 3 (rarely 4) sporangia fused into a single synangium, and borne in the axils of minute and bract-like or larger and leaf-like bifid sporophylls; homosporous; axis not differentiated into roots (Psilotophyta)... Psilotaceae
Sporangia free, borne axillary on sporophylls which are often condensed into strobili; homosporous or heterosporous; axis with differentiated roots... ... 3
3 Plants cylindrical with regular sheathed nodes, scariose, bract-like leaves borne in a single whorl at each node, the stem photosynthetic, hollow, containing many silica crystals; homosporous, spores chlorophylous (Equisetophyta)... Equesitaceae
Plants not cylindrical, bearing expanded photsynthetic leaves; homosporous or heterosporous, spores not chlorphyllous (Lycopodiophyta)... ... 4
4 Aquatic (occasionally terestrial) rosette herbs with a thickened, compact, corm-like axis; leaves linear with 4 large longitudinal air-chambers Isoetaceae
Terrestrial or epiphytic herbs, never rosettes nor corm-like, axis elongate and mostly branched; leaves short, without air-chambers ... 5
5 Heterosporous; leaves ligulate, 4-ranked, decussate but mostly dorsiventral with 2 larger rows beneath and 2 smaller rows above; stem often supported by stilt-like rhizophores at intervals... Selaginellaceae
Homosporous; leaves eligulate, mostly arranged in close spirals, sometimes decussate, sometimes dorsiventrally flattened with all but 2 rows reduced; supported by clusters of roots Lycopodiaceae

See also:

References

Andrews, S.B. 1990. Ferns of Queensland. A handbook to the ferns and fern allies. Queensland Dept. Primary Industries, Brisbane.

Brownlie, G. 1969. Flore de la Nouvelle-Caledonie et dependances. 3. Pteridophytes. Museum National d'Histoire Naturelle, Paris.

Brownlie, G. 1977. The pteridophyte flora of Fiji. J.Cramer, Vaduz.

Brownsey, P.J. & Smith-Dodsworth, J.C. 1989. New Zealand ferns and allied plants.

Brummitt, R.K. 1992. Vascular plant families and genera. Royal Botanic Gardens, Kew, England.

Chinnock, R.J. 1986. Division 1. Pteridophyta. In Jessop,J.P. & Tolken, H.R. (eds.) Flora of South Australia 1: 78 - 103. Government Printer, Adelaide.

Chinnock, R.J. & Henshall, T.S. 1981. Pteridophyta. In Jessop, J.P. (ed.) Flora of Central Australia 6- 13. A.H. & A.W. Reed, Sydney.

Clifford, H.T. & Constantine, J. 1980. Ferns, fern allies and conifers of Australia. Univ. Queensland Press, St Lucia.

Duncan, B.D. & Isaac, G. 1986. Ferns and allied plants of Victoria, Tasmania and South Australia. Melbourne University Press, Carlton, Victoia.

Edie, H.H. 1978. Ferns of Hong Kong. Libra Press, Hong Kong.

Entwhistle, T.J. 1996. Ferns and allied plants (Psilophyta, Lycopodiophyta, Polypodiophyta). Fl. Victoria. 2: 13 - 111.

Garrett, M. 1996. The ferns of Tasmania: their ecology and distribution. Tasmanian Forest Research Council. Hobart

George, A.S., Orchard, A.E & Hewson, H.J. (eds.) Flora of Australia, volume 50. Oceanic Islands 2. AGPS, Canberra.

Harden, G.J. 1996. Flora of New South Wales, volume 1. NSW Univ. Press, Kennsington.

Heath, E. & Chinnock, R.J. 1974. Ferns and fern allies of New Zealand. A.H. & A.W. Reed, Wellington.

Holttum, R.E. 1954. Revised Flora of Malaya II. Ferns of Malaya. Govt. Printing Office, Singapore.

Holttum, R.E. (ed.) 1959. Flora Malesiana, series II, volume 1(1). Noordhoff International Publishing, Leiden.

Jacobsen, W.B.G.. 1983. The ferns and fern allies of southern Africa. Butterworth, Durban.

Jermy, A.C., Crabbe, J.A. & Thomas, B.A. (eds.) 1973. The phylogeny and classsification of the ferns. Academic Press, London.

Jones, D.L.. 1987. Encyclopaedia of ferns. An introduction to ferns, their structure, biology, economic importance, cultivation and propagation. Lothian, Port Melbourne.

Jones, D.L. & Clemesha, S.C.. 1976. Australian ferns and fern allies. A.H. & A.W. Reed, Sydney.

Jones, D.L. & Clemesha, S.C.. 1981. Australian ferns and fern allies. (ed. 2) A.H. & A.W. Reed, Sydney.

Kubitzki, K. (ed.) 1990. The families and genera or vascular plants. Vol. 1. Pteridophytes and gymnosperms. Springer-Verlag, Berlin.

McCarthy, P.M. (ed.) 1998. Flora of Australia, volume 48. Ferns, gymnospersms and allied groups. ABRS/CSIRO, Australia.

Orchard, A.E & (ed.) Flora of Australia, volume 49. Oceanic Islands 1. AGPS, Canberra.

Sporne, K.R. 1975. The morphology of the pteridophytes. Hutchinson, London.

Tryon, R.M. & Tryon, A.F. 1982. Ferns and allied plants, with special reference to tropical America. Springer-Verlag, New York.

Willis, J.C. 1973. A dictionary of the flowering plants and ferns. (ed. 8, revised by Airy Shaw, H.K.) Cambridge University Press, Cambridge.


Updated November 1999 by Jim Croft (jim.croft@environment.gov.au)