Skip to content

SYNOPTIC DESCRIPTION OF THE PHYLUM PTERIDOPHYTA

SYNOPTIC DESCRIPTION OF THE PHYLUM PTERIDOPHYTA

EUKARYA> ARCHAEPLASTIDA> VIRIDIPLANTAE> STREPTOBIONTA> EMBRYOPHYTA> TRACHEOPHYTA> PTERIDOPHYTA
PTERIDOPHYTA LINKS

Introduction

Hierarchical Classification

The following description comes from Bold et al. (1987), Lellinger (1985), Bierhorst (1971), and Kenrick and Crane (1997b).

I. SYNONYMS: ferns, Polypodiophyta, Filicinophyta, and Moniliformopses.

II. NUMBER: 9,000-12,000 species extant ferns

III. PHYLUM CHARACTERISTICS

  • A. Structure
  • Gametophyte: Small, thalloid, usually photosynthetic; gametophyte grows within the bounds of the spore wall in some. Some are heterothallic.
  • Sporophyte: Herbaceous; extant species generally rhizomatous (text with tooltip) Plants having rhizomes (horizontal stems, often underground or on the surface of the ground, bearing scale-like leaves). with megaphylls (text with tooltip) An megaphyll (=macrophyll) is a leaf that is derived from a lateral branch system which became webbed. Most extant vascular plants have macrophylls. and ]adventitious roots (text with tooltip) Adventitious is derived from the past participle of a Latin verb that means to arrive (adventum). The meaning in this context is something that is extra or foreign. Adventitious roots develop secondarily from stem axes. . This is highly variable and ranges from small floating plants to palm-like trees. Though the megaphylls are the primary photosynthetic organs in most taxa, the stems in Psilotum and Equisetum function as the primary photosynthetic organs.
  • Spores: Homosporous (text with tooltip) Homosporous (adj) plants produce one type of spore. to heterosporous (text with tooltip) Heterosporous plants have sporangia that produce spores of different sizes: megaspores (large) and microspores (small). Megaspores produce archegoniate gametophytes, and microspores produce antheridial gametophytes. .
  • Sporangia: Thick-walled eusporangia (text with tooltip) A eusporangium is the most common spore-bearing structure in plants. Eusporangia develop from more than one cell and usually have a wall of several cell layers. Contrast a eusporangium with a leptosporangium. or smaller leptosporangia (text with tooltip) A leptosporangium is a small, usually stalked, sporangium that develops from a single superficial cell. Contrast this with a eusporangium. associated with the abaxial side of fertile megaphylls. Sporangia are usually clustered in fertile regions called sori (text with tooltip) A sorus is a fertile region (sporangium-bearing region) on a leaf. . Highly specialized sporangial structures have evolved in the Salviniales, the Equisetales, the Psilotopsida, and the Marattiopsida. The sporangiophores (text with tooltip) Sporangiophores are fertile appendages that do not look leaf-like. The sporangiophores of the horsetails may be compound structures. of the Equisetales are most distinctive.
  • Stele: Their axes vary in complexity with steles of almost all types possible: protosteles, actinosteles, plectosteles (text with tooltip) A plectostele is a modified actinostele in which the segments are deeply cut and divided in the common cortex. , ectophloic siphonosteles (text with tooltip) An ectophloic siphonostele is a type of siphonostele with phloem in a ring ouside of the xylem. , amphiphloic siphonosteles (text with tooltip) An amphiphloic siphonostele (=solenostele) is a type of siphonostele with phloem in rings on the inside and outside of the xylem. (solenosteles), dictyosteles (text with tooltip) A dictyostele is amphiphloic siphonostele that is separated into segments in the stem cortex. , and eusteles (text with tooltip) A eustele is a stele type characteristic of most seed-bearing plants and a few ferns and fern allies. Although other stele types can function to make wood, the eustele is the most common one. Vascular bundles characteristically are arranged in a circle around a region of pith. The cortical parenchyma is continuous with the pith through rays which separate the vascular bundles. Xylem is on the inside and phloem is on the outside of each bundle. .
  • Leaves: Megaphylls (text with tooltip) An megaphyll (=macrophyll) is a leaf that is derived from a lateral branch system which became webbed. Most extant vascular plants have macrophylls. which emerge by circinate vernation (text with tooltip) Circinate vernation is a type of leaf (or axis) emergence in which the appendage unrolls. The products of circinate vernation are called fronds. in most. Indeed, most taxa have compound leaves, some up to four times compound.
  • Roots: Present; usually adventitious; protostelic.
  • Life Histories of:
    • Psilotum, a homosporous, eusporangiate fern
    • Equisetum, a homosporous eusporangiate fern with distinctive strobili (text with tooltip) A strobilus is an axis of fertile appendages. A simple strobilus is an axis of sporophylls. A compound strobilus is an axis of simple fertile axes. Sometimes the compound cones have simple fertile axes that are reduced to a single sporophyll and appear to be simple strobili. of sporangiophores
    • Pteridium, a homosporous, leptopsporangiate fern
    • Marsilea, a heterosporous fern
  • B. Ecology: Variable, from terrestrial and epiphytic to aquatic and semi-aquatic; found from tropics to subarctic regions.
LITERATURE CITED

Bierhorst, D. W. 1971. Morphology of Vascular Plants. In: N. H. Giles and J. G. Torrey. The MacMillan Biology Series. The MacMillan Co. New York.

Bold, H. C., C. J. Alexopoulos, and T. Delevoryas. 1987. Morphology of Plants and Fungi. 5th Edition. HarperCollins Publishers, Inc. New York.

Galtier, J. and F. M. Hueber. 2001. How early ferns became trees. Proc. R. Soc. Lond. B. 268: 1955-1957.

Kenrick, P. and P. R. Crane. 1997b. The Origin and Early Diversification of Land Plants: A Cladistic Study. Smithsonian Institute Press. Washington, D.C.

Lellinger, D. B. 1985. A Field Manual of the Ferns and Fern-Allies of the United States and Canada. Smithsonian Institution Press. Washington, D.C.

Pearson, L. C. 1995. The Diversity and Evolution of Plants. CRC Press. New York.

Pryer, K. M., H. Schneider, A. R. Smith, R. Cranfill, P. G. Wolf, J. S. Hunt, and S. D. Sipes. 2001a. Horsetails and Ferns are a Monophyletic Group and the Closest Living Relatives to Seed Plants. Nature. 409:618-622.

Pryer, K. M., E. Schuettpelz, P. G. Wolf, H. Schneider, A. R. Smith, R. Cranfill. 2004. Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences. American Journal of Botany. 91(10): 1582-1598.

Rothwell, G. W. 1999. Fossils and ferns in the resolution of land plant phylogeny. Botanical Review 65:188-218.

Schneider, H., A. R. Smith, and K. M. Pryer. 2009. Is morphology really at odds with molecules in estimating fern phylogeny? Systematic Botany. 34(3): 455-475.

Schuettpelz, E., P. Korall, and K. M. Pryer. 2006. Plastid atpA data provide improved support for deep relationships among ferns. Taxon. 55(4): 897-906.

Schuettpelz, E. and K. M. Pryer. 2007. Fern phylogeny inferred from 400 leptosporangiate species and three plastid genes. Taxon. 56(4): 1037-1050.

Schuettpelz, E. and K. M. Pryer. 2008. Fern phylogeny. In: Ranker, T. A. and C. H. Haufler, eds. Biology and Evolution of Ferns and Lycophytes. Cambridge University Press. Cambridge. pp. 395-416.

Smith, A. R., K. M. Pryer, E. Schuettpelz, P. Korall, H. Schneider, and P. G. Wolf. 2006. A classification for extant ferns. Taxon. 55(3): 705-731.

Smith, G. M. 1955. Cryptogamic Botany. Vol II. Bryophytes and Pteridophytes. 2nd ed. McGraw-Hill Book Co., Inc. New York.

Soria, A. and B. Meyer-Berthaud. 2004. Tree fern growth strategy in the late Devonian cladoxylopsid species Pietzschia levis from the study of its stem and root system/ American Journal of Botany. 91(1): 10-23.

Stein, W. E., F. Mannolini, L. A. Hernick, E. Landing, and C. M. Berry. 2007. Giant cladoxylopsid trees resolve the enigma of the Earth’s earliest forest stumps at Gilboa. Nature. 446: 904-907.

Stewart, W. N. and G. W. Rothwell. 1993. Paleobotany and the Evolution of Plants. 2nd edition. Cambridge University Press. Cambridge.

Thomas, B. A. and R. A. Spicer. 1987. The Evolution and Palaeobiology of Land Plants. Diocorides Press. Ecology, Phytogeography, and Physiology Series. Vol 2. Portland, Oregon.

Tomescu, A. M. F. 2008. Megaphylls, microphylls and the evolution of leaf development. Trends in Plant Science. 14(1): 5-12.

Wikstrom, N. and K. M. Pryer. 2005. Incongruence between primary sequence data and the distribution of a mitochondrial atp1 group II intron among ferns and horsetails. Molecular Phylogenetics and Evolution. 36: 484-493.
By Jack R. Holt. Last revised: 03/26/2013
Print Friendly, PDF & Email

Document Footer

Skip to toolbar