• Butler, W. L., Hendricks, S. B. & Siegelman, H. W. (1964). Action spectra of phytochrome in vitro. Photochemistry and Photobiology, 3, 521528.
  • Frankland, B. (1981). Germination in shade. In: Plants and the Daylight Spectrum (Ed. by H.Smith), pp. 187204. Academic Press, New York .
  • Grime, J. P. & Jabvis, B. C. (1975). Shade avoidance and shade tolerance in flowering plants. II. Effects of light on the germination of species of contrasted ecology. In: Light as an Ecological Factor (Ed. By R.Bainbridge, G. C.Evans & O.Rackham), pp. 525532. Blackwell Scientific Publications, Oxford .
  • Harper, J. L. (1959). The ecological significance of dormancy. Proceedings IV International Congress for Crop Protection (Hamburg, 1957), pp. 415420.
  • Holmes, M. G. & Smith, H. (1977). The function of phytochrome in the natural environment. II. The influence of vegetation canopies on the spectral distribution of natural daylight. Photochemistry and Photobiology, 25, 539545.
  • Morgan, D. C. & Smith, H. (1979). A systematic relationship between phytochrome photoequilibrium controlled development and species habitat for plants grown m simulated natural radiation. Planta, 145, 253258.
  • Thompson, K., Grime, J. P. & Mason, G. (1977). Seed germination in response to diurnal fluctuations of temperature. Nature, 267, 147149.