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HIERARCHICAL CLASSIFICATION OF THE PHYLUM LYCOPODOPHYTA

HIERARCHICAL CLASSIFICATION OF THE PHYLUM LYCOPODOPHYTA

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

Introduction

Synoptic Description

The following taxonomy is taken from Bold et al. (1987), but modified by Kenrick and Crane (1997). Of the 6 orders, 3 are entirely extinct. We have indicated the highest taxon in a group that is extinct. with a cross (+) and all entirely extinct taxa are in maroon letters.

CLASS LYCOPODIOPSIDA (AGLOSSOPSIDA in Bold et al. 1987)

The plants are homosporous and do not show secondary growth.

  • ORDER ASTEROXYLALES+ (=DREPANOPHYCALES)
    • These plants are extinct with a fossil history in the Devonian period. Stalked sporangia are scattered on the axes rather than on microphylls. They do not have true roots. Vascular tissue invades only the base of the leaves.
    • Asteroxylon, Drepanophycus, Baragwanathia.
  • ORDER LYCOPODIALES
    • These plants are extant but have a fossil history which goes back to the upper Devonian. The microphylls are closely spaced on the stem and sporophylls are clustered in strobili.
    • Lycopodium, Huperzia, Lycopodites+.
  • ORDER PROTOLEPIDODENDRALES+
    • These plants are extinct and mainly from the Devonian. The microphylls have expanded leaf bases and forked tips. The sporophylls are loosely associated in strobili.
    • Protolepidodendron, Leclercqia.

CLASS SELAGINELLOPSIDA (=GLOSSOPSIDA in Bold et al. 1987)

These plants are heterosporous with gametophytes rarely exceeding the bounds of the spore wall. Ligules are associated with the leaves. Most show secondary growth, even if it is weak.

  • ORDER LEPIDODENDRALES+
    • These plants are extinct with a fossil history from the Carboniferous through the Triassic periods. They are tree-like with siphonostelic stems and a cortical cambium. The sporangia are massive.
    • Lepidodendron, Lepidocarpon, Lepidophloios, Phytokneme, Sigillaria, Stigmaria
  • Incertae Sedis
    • These plants were upright (ca 2m), unbranched with long strap-like leaves. The trunk sat on a base with four lobes. They flourished in the Triassic.
    • Pleuromeia.
  • ORDER SELAGINELLALES
    • These plants are extant and have a fossil history from the Carboniferous. Plants with scale-like leaves; some are anisophyllous.
    • Selaginella, Selaginellites+
  • ORDER ISOETALES
    • These plants are extant with a fossil history which dates back to the Cretaceous (although it is probably much older). The stems are reduced but exibit secondary growth. The leaves are quill-like.
    • Isoetes, Nathorstiana+, Isoeites+, Stylites+.
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.

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

Cronquist, A., A. Takhtajan, and W. Zimmermann. 1966. On the higher taxa of Embryobionta. Taxon. 15(15): 129-134.

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.

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.

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.

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.
By Jack R. Holt. Last revised: 03/25/2013
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