Gray, J. (1985) ‘The microfossil record of early land plants: advances in understanding of early
terrestrialization, 1970–1984’, Philosophical Transactions of the Royal Society, London, B309:
167–95.
—— (1991) ‘Tetrahedraletes, Nodospora, and the “cross” tetrad: an accretion of myth’, in
S.Blackmore and S.H.Barnes (eds) Pollen and Spores, Patterns of Diversification, Systematics
Association Special Volume 44, Oxford: Clarendon Press, pp. 49–87.
—— (1993) ‘Major Paleozoic land plant evolutionary bio-events’, Palaeogeography,
Palaeoclimatology, Palaeoecology, 104:153–69.
Gray, J. and Boucot, A.J. (1971) ‘Early Silurian spore tetrads from New York: earliest New World
evidence for vascular plants?’, Science, 173:918–21.
—— (1977) ‘Early vascular land plants: proof and conjecture’, Lethaia, 10:145–74.
Gray, J., Massa, D. and Boucot, A.J. (1982) ‘Caradocian land plant microfossils from Libya’,
Geology, 10:197–201.
Habgood, K.S. (2000) ‘Two cryptospore-bearing land plants from the Lower Devonian
(Lochkovian) of the Welsh Borderland’, Botanical Journal of the Linnean Society, 133:203–27.
Harland, W.B., Armstrong, R.L., Cox, A.V., Craig, L.E., Smith, A.G. and Smith, D.G. (1990) ‘A
Geologic Timescale 1989’, Cambridge: Cambridge University Press.
Heckman, D.S., Geiser, D.M., Eidell, B.R., Stauffer, R.L., Kardos, N.L. and Hedges, S.B. (2001)
‘Molecular evidence for the early colonization of land by fungi and plants’, Science, 293:
1129–33.
Hemsley, A.R. (1994) ‘The origin of the land plant sporophyte: an interpolation scenario’, Biological
Reviews, 69:263–73.
Hoffmeister, W.S. (1959) ‘Lower Silurian plant spores from Libya’, Micropalaeontology, 5:331–4.
Horodyski, R.J. and Knauth, L.P. (1994) ‘Life on land in the Precambrian’, Science, 263:494–8.
Hueber, F.M. (2001) ‘Rotted wood-alga-fungus: the history and life of Prototaxites Dawson 1859’,
Review of Palaeobotany and Palynology, 116:123–58.
Johnson, N.G. (1985) ‘Early Silurian palynomorphs from the Tuscarora Formation in central
Pennsylvania and their paleobotanical and geological significance’, Review of Palaeobotany and
Palynology, 45:307–60.
Karol, K.G., McCourt, R.M., Cimino, M.T. and Delwiche, C.F. (2001) ‘The closest living relative
of land plants’, Science, 294:2351–3.
Keller, C.K. and Wood, B.D. (1993) ‘Possibility of chemical weathering before the advent of
vascular land plants’, Nature, 364:223–5.
Kenrick, P. (2000) ‘The relationships of vascular plants’, Philosophical Transactions of the Royal
Society, London, B355:847–55.
Kenrick, P.K. and Crane, P.R. (1997) ‘The Origin and Early Diversification of Land Plants’,
Washington: Smithsonian Institution Press.
Knoll, A.H. and Bambach, R.K. (2000) ‘Directionality in the history of life: diffusion from the left
wall or repeated scaling of the right?’, Paleobiology, 26 (supplement): 1–14.
Kodner, R.B. and Graham, L.E. (2001) ‘High-temperature, acid-hydrolyzed remains of Polytrichum
(Musci, Polytrichaceae) resemble enigmatic Silurian-Devonian tubular microfossils’, American
Journal of Botany, 88:462–6.
Kroken, S.B., Graham, L.E. and Cook, M.E. (1996) ‘Occurrence and evolutionary significance of
resistant cell walls in charophytes and bryophytes’, American Journal of Botany, 83:1241– 54.
Kurmann, M.H. and Doyle, J.A. (1994) ‘Ultrastructure of Fossil Spores and Pollen: Its Bearing on
Relationships Among Fossil and Living Groups’, Kew: The Royal Botanic Gardens.
Lang, W.H. (1937) ‘On the plant-remains from the Downtonian of England and Wales’,
Philosophical Transactions of the Royal Society, London, B227:245–91.
142 CHARLES H.WELLMAN