present, largely due to problems with the actual techniques and in interpreting the data. It
is suggested that a widespread and abundant early land plant dispersed spore record would
develop soon after the origin of land plants, as these structures, which are vital for the
invasion of land, have high fossilization potential, would have been produced in vast
numbers, and would have been widely distributed (in addition to palaeogeographical
spread of the founder populations being rapid).
AcknowledgementsThe research reported in this chapter was supported by the NERC research grant NER/B/
S/2001/00211. I would like to thank Dr Paul Kenrick for an insightful review of an
earlier draft of the manuscript.
ReferencesBanks, H.P. (1975) ‘The oldest vascular land plants: a note of caution’, Review of Palaeobotany and
Palynology, 20:13–25.
Blackmore, S. and Barnes, S.H. (1987) ‘Embryophyte spore walls: origin, homologies and
development’, Cladistics, 3:185–95.
Blum, J.D. (1997) ‘The effect of Late Cenozoic glaciation and tectonic uplift on silicate weathering
rates and the^87 Sr/^86 Sr record’, in W.F.Ruddiman (ed.) Tectonic Uplift and Climate Change, New
York: Plenum.
Blum, J.D., Gazis, C.A., Jacobson, A.D. and Chamberlin, C.P. (1998) ‘Carbonate versus silicate
weathering in the Raikhot watershed within the High Himalayan Crystalline Series’, Geology,
26:411–14.
Boucot, A.J. and Gray, J. (2001) ‘A critique of Phanerozoic climatic models involving changes in
the CO 2 content of the atmosphere’, Earth Science Reviews, 56:1–159.
Broecker, W.S. and Sanyal, A. (1998) ‘Does atmospheric CO 2 police the rate of chemical
weathering’, Global Biogeochemical Cycles, 12:403–8.
Burgess, N.D. and Edwards, D. (1991) ‘Classification of uppermost Ordovician to Lower Devonian
tubular and filamentous macerals from the Anglo-Welsh Basin’, Botanical Journal of the Linnean
Society, 106:41–66.
Cai, C., Ouyang, S., Wang, Y., Fang, Z., Rong, J., Geng, L. and Li, X. (1996) ‘An Early Silurian
vascular plant’, Nature, 379:592.
Edmond, J.M. (1992) ‘Himalayan tectonics, weathering processes, and the strontium isotope
record in marine limestones’, Science, 258:1594–7.
Edmond, J.M. and Huh, Y. (1997) ‘Chemical weathering yields from basement and orogenic
terrains in hot and cold climates’, in W.F.Ruddiman (ed.) Tectonic Uplift and Climate Change, New
York: Plenum, pp. 329–51.
Edwards, D. (1996) ‘New insights into early land ecosystems: a glimpse of a Lilliputian world’,
Review of Palaeobotany and Palynology, 90:159–74.
—— (2000) ‘The role of mid-Palaeozoic mesofossils in the detection of early Bryophytes’,
Philosophical Transactions of the Royal Society, London, B355:733–55.
Edwards, D. and Richardson, J.B. (1996) ‘Review of in situ spores in early land plants’, in
J.Jansonius and D.C.McGregor (eds) Palynology: Principles and Applications., Salt Lake City,
140 CHARLES H.WELLMAN