Errata: Corynephorus Canescens (L.) P. Beauv. as a Model for the Ammophila Problem

Abstract

Corynephorus canescens, a tufted perennial, 10-30 cm high, is a widespread plant of European coastal and inland sand dunes where it often forms a major component of the vegetation. In Britain it is much rarer, being present in abundance only on the coastal dunes of East Anglia (Marshall 1964). The experimental study to be described was concentrated on the populations of Corynephorus on the National Nature Reserve north of Winterton, Norfolk, a description of which appears in Steers & Jensen (1953), but was supplemented by comparisons with populations from other dune systems. C. canescens and Ammophila arenaria behave somewhat similarly in relation to sand accretion. In areas where there is accretion up to 40 cm per annum for Ammophila and up to 10 cm per annum for Corynephorus, they grow vigorously. The plants are large, green and fresh in appearance, there is an abundance of new root production and flowering occurs freely. On areas of stable dune, however, both grasses show a marked decline in vigour, they are smaller, there is litter accumulation, the development of new roots is rare and there is sometimes a decline in flowering. Ammophila exhibits a tussock growth form in comparison with the more uniform shoot distribution in unstable areas (GreigSmith 1961). This decline in vigour of Ammophila has been commented on in the literature for over 100 years (early literature cited in Marshall 1963) and many authors have suggested reasons to account for it though these are rarely based on an experimental study (Table 1). It is noteworthy that the reasons listed in Table 1 take relatively little account of factors associated with the morphology of this highly specialized species and its pattern of growth in a changing environment. Further discussion of the reasons presented in Table 1 is deferred to Section IV (ii); the reasons are considered in relation to Corynephorus in Section II (ii). The intractability of Ammophila as an experimental plant, due to its size, was obviated in the present study by using Corynephorus as a model for the problem because it responds similarly to stable dune conditions.