The earliest vascular plants can be found in rocks from the Middle Silurian.
The first plants were very small but in rocks in Australia from the end of the Silurian plants were found exceeding 30 cm in length.
In the early Devonian plants started to radiate and four different groups of plants can be distinguished: the Lycopods, the Rhyniophytes, the Trimerophythes and the Zosterophyllophytes. From the famous silicified material from the Rhynie Chert, a lower Devonian sinter deposit with exceptionally preserved plants and animals much has been learned about early plant life.
References:
- Berry, C.M. and Hilton, J., 2006, Givetian (Middle Devonian) cladoxylopsid ‘ferns’ from Orkney, northern Scotland, Transactions of the Royal Society of Edinburgh: Earth Sciences, 97, 65–73
- Cleal, C.J.and Thomas, B.A. 1995, Palaeozoic Palaeobotany of Great Britain, CHAPMAN & HALL (book).
- Lang, W. H. 1925. Contributions to the study of the Old Red Sandstone flora of Scotland. 1. On plant remains from the fish-beds of Cromerty. 2. On a sporangium-bearing branch-system from the Stromness Beds. Trans. Roy. Soc. Edinburgh, 54, 253-279.
- Peach, C. W., 1879, On the fossil plants found in the Old Red Sandstone of Shetland, Orkney, Caithness, Sutherland and Forfarshire, Transactions of the Edinburgh Geological Society, v.3; p148-152.
- Trewin N.H., and C. M. Rice, 1992 Stratigraphy and sedimentology of the Devonian Rhynie chert locality, Scott. J. Geol. 28, (1), 37-47