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HIERARCHICAL CLASSIFICATION OF THE PHYLUM RHYNIOPHYTA

HIERARCHICAL CLASSIFICATION OF THE PHYLUM RHYNIOPHYTA

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

Introduction

Synoptic Description

This system is a modification of Kenrick and Crane (1997), Bold et al. (1987), and Bierhorst (1971).

CLASS HORNEOPHYTOPSIDA

These were small plants (about 20 cm tall) with an endarch central strand. The xylem cells had a reticulate thickening around the cell wall. The base of the stem is swollen (corm-like) with rhizoids emerging from them. Terminal sporangia are cylindrical and branched. Also, they have a columella. The archegonial gametophyte has been identified. It is upright (about 6cm high) with archegonia at the terminal ends. Lower Devonian

  • ORDER HORNEOPHYTALES
    • Horneophyton

CLASS NOT SPECIFIED

The single genus in this class superficially resembles Rhynia. Indeed, it was formerly called R. major. It is part of the Rhynie Chert assemblage of plants, but it has characters that cause Kenrick and Crane (1997) to question its position as a vascular plant. That is, its water-conducting cells are smooth and tapered, more like the hydroids of Polytrichum. The central strand is endarch in its maturation pattern and the stems, which are about 15 cm high show a pattern of sparse dichotomous branching. The terminal sporangia are fusiform and dehisce obliquely. The gametophyte (the antheridial gametophyte) has been identified as a small aerial plant with cup-like structures on which the antheridia occur. Lower Devonian

  • ORDER NOT SPECIFIED
    • Agalophyton

CLASS RHYNIOPSIDA

This is the most diverse group of plants in this phylum. All (except Nothia) have xylem cells with annular rings. Because Nothia seems otherwise advanced, the absence of annulations would seem to be a loss rather than a primitive condition. All have an endarch pattern of development. The upright stems emerge from branched prostrate axes. The upright stems branch dichotomously, or with slight unequal branching. Some branches terminate in sporangia that range from fusiform to globose to reniform. Some taxa are quite robust and grow to 50 cm high. Middle Silurian to Middle Devonian

  • ORDER RHYNIALES
    • Rhynia, Cooksonia, Steganotheca, Uskiella, Hicklingia, Eogaspesiea, Taeniocrada, Hediea, Yarravia, Hostomella, Nothia?
LITERATURE CITED

Banks, H. P. 1975. Reclassification of Psilophyta. Taxon. 24: 401-413.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.

Boyce, C. K. 2008. How green was Cooksonia? The importance of size in understanding the early evolution of physiology in the vascular plant lineage. Paleobiology. 34(2): 179-194.

Crane, P. R., P. Herendeen, and E. M. Friis. 2004. Fossils and plant phylogeny. American Journal of Botany. 91(10): 1683-1699.

Doyle, J. A. 1998b. Phylogeny of vascular plants. Annual Review of Ecology and Systematics. 29:567-599.

Fenton, C. L. and M. A. Fenton 1958. The Fossil Book. Doubleday and Co., Inc. New York.

Friedman, W. E. and M. E. Cook. 2000. The origin and early evolution of tracheids in vascular plants: integration of palaeobotanical and neobotanical data. Phil. Trans. R. Soc. Lond. B. 355:857-868.

Gensel, P. G. and C. M. Berry. 2001. Early lycophyte evolution. American Fern Journal. 91(3): 74-96.

Judd, W. S., C. S. Campbell, E. A. Kellogg, P. F. Stevens, and M. J. Donoghue. 2008. Plant Systematics: A Phylogenetic Approach. 3rd edition. Sinauer Associates, Inc. Sunderland, MA.

Keeley, J. E. 1981. Isoetes howellii: A submerged aquatic CAM plant? American Journal of Botany. 68(3): 420-424.

Kenrick, P. and P. R. Crane. 1997b. The origin and early diversification of land plants: a cladistic study. Smithsonian Institute Press. Washington, DC.

Kerp, H., H. Hass, and V. Mosbrugger. 2001. New data on Nothia aphylla Lyon, 1964 ex El Saadawy et Lacey, 1979: a poorly known plant from the Lower Devonian Rhynie chert. In: Gensel, P. G. and D. Edwards, eds. Plants invade the land: evolutionary and environmental perspectives. Columbia University Press, New York, pp. 52-82.

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company. New York.

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, and 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.

Qiu, Y.-L. and J. D. Palmer. 1999. Phylogeny of early land plants: insights from genes and genomes. Trends in Plant Science. 4(1): 26-30.

Qiu, Y.-L., L. Libo, B. Wang, Z. Chen, V. Knoop, M. Groth-Malonek, O. Dombrovska, J. Lee, L. Kent, J. Rest, G. F. Estabrook, T. A. Hendry, D. W. Taylor, C. M. Testa, M. Ambros, B. Crandall-Stotler, R. J. Duff, M. Stech, W. Frey, D. Quandt, and C. C. Davis. 2006. The deepest divergences in land plants inferred from phylogenomic evidence. Proceedings of the National Academy of Science. USA. 103(42): 15511-15516.

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.
By Jack R. Holt. Last revised: 03/21/2013
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