The Invasion of the Land
The early manifestations of life detailed in Chapter 2 and those plants described in Chapter 3 gave rise to organisms from which land plants might evolve. A detailed study of early vascular plants, then, should shed light on the speed and direction of their evolution. The patterns of early vascular plant evolution have long fascinated botanists, and there is voluminous literature on the subject. However, many conclusions that have been drawn suffer from two serious deficiencies. First, the number of plants proven to be vascular is small, and details of their structure are extremely limited. Second, the precise age of the rock strata whence they have been collected has often been unknown or unrecorded, or has been revised in accordance with new data provided by animal paleontology and stratigraphy. The viewpoint presented here relies on newer studies that have added markedly to our knowledge of the plants themselves and on more recent analyses of the age of the various subdivisions of Devonian time (Table 4-1). Underlying the various descriptions that follow are the ever-present questions: Do the early plants resemble those we know today? How rapidly did the first land plants become diversified? Are there some early plants which appeared and then became extinct? Can we find early plants that were successful on the new terrestrial environment and from which other forms may be descended?
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Suggestions for Further Reading
- Banks, H. P., “The Early History of Land Plants,” in Ellen T. Drake, ed., Evolution and Environment, (New Haven and London: Yale University Press, 1968), pp. 73–107. Gives a full description of major types of early land plants.Google Scholar
- Banks, H. P., “The Stratigraphic Occurrence of Early Land Plants and Its Bearing on Their Origin,” (1968), pp. 721–730. In D. H. Oswald (ed.) International Symposium on the Devonian System, Vol. I. Alberta Society of Petroleum Geologists, Calgary, Canada.Google Scholar
- Banks, H. P., and M. R. Davis, “Crenaticaulis, a New Genus of Devonian Plants Allied to Zosterophyllum, and Its Bearing on the Classification of Early Land Plants,” American Journal of Botany, 69 (1969). Gives many details of one zosterophyll.Google Scholar
- Boureau, E., ed., Traité de Paléobotanique II (Paris: Masson et Cie, Editeurs, 1967). See especially Hoeg, O. A., Psilophyta, and Chaloner, W. G., Lycophyta. This treatment includes excellent IIIustrations of all important Devonian psilophytes and lycopods.Google Scholar
- Edwards, D., and H. P. Banks, “Branching in Gosslingia Breconensis,” American Journal of Botany, 52 (1965), p. 636.Google Scholar
- Grierson, J. D., and H. P. Banks, “Lycopods of the Devonian of New York State,” Palaeontographica Americana, 4 (1963), pp. 219–295. A comprehensive treatment of Devonian lycopods.Google Scholar
- Hueber, F. M., “Psilophyton: The Genus and the Concept,” in D. H. Oswald, ed., International Symposium on the Devonian System, Vol. 2, Alberta Society of Petroleum Geologists, Calgary, Canada, (1968), pp. 815–822. The definitive treatment of well-known Devonian genus.Google Scholar
- Jaeger, H., “Two Late Monograptus Species from Victoria, Australia, and Their Significance for Dating the Baragwanathia Flora,” Proceedings of the Royal Society of Victoria, 79 (1966), pp. 393–413. Discusses the importance of graptolites in dating plant-bearing strata.Google Scholar
- Lang, W. H., and I. C. Cookson, “On a Flora Including Vascular Land Plants, Associated with Monograptus, in Rocks of Silurian Age, from Victoria, Australia,” Philosophical Transactions of the Royal Society of London 224B (1935), pp. 421–449. Discusses Australian plants earlier thought to be Silurian in age.CrossRefGoogle Scholar
- Obrhel, J., “Die Flora der Pridoli-Schichten (Bundnany-Stufe) des mittelböhmischen Silurs,” Geologie 11 (1962), pp. 83–97. Discusses what is thought to be the oldest vascular plant.Google Scholar
- Walton, J., “On the Morphology of Zosterophyllum and Some Other Devonian Plants,” Phytomorphology, 14 (1964), pp. 155–160. A good reconstruction of the habit of Zosterophyllum.Google Scholar