1. Thorley, A. in Guide to Sussex Excursions (ed. Williams. R.B.G.) 47 (IBG Conf., 1971).
2. Godwin, H. Veröff. Geobot. Inst. Rübel Zurich 37, 83 (1962).
3. Brookcs, A. Unpublished data from Wellingham, Sussex.
4. Allison, J. & Godwin, H. New Phytol. 48, 253 (1949).
5. Conolly, A.P. New Phytol. 40, 299 (1941).