SM26: Inula crithmoides on salt-marshes

Summary

Inula crithmoides is a maritime perennial largely confined to southern England and Wales: it is recorded from Essex round to Anglesey with an isolated station in south-west Scotland (Perring & Walters 1962). Although it occurs in maritime cliff communities throughout its range, occurrences in salt-marsh vegetation are restricted to south-east England from Essex to Hampshire.

Here it is an occasional in various associations but it is sometimes encountered in abundance, usually with Halimione portulacoides as a co-dominant. In the few available samples there is a distinction between stands where Puccinellia maritima, annual Salicornia spp. and Limonium cf. vulgare are constant in generally small amounts and those which have abundant Elymus pycnanthus. The former occur on low-marsh sites with coarse sand; the latter on moderately organic soils with much drift litter on the upper marsh.

Ranwell (1972; Ranwell & Boorman 1977) has correlated the distribution of I. crithmoides on salt-marshes with the occurrence of lime-rich freshwater influence and the presence of Chalk bedrock near the surface. Though this may be true, it is difficult to see the ecological significance of the observation: most salt-marshes are alkaline to some degree and I. crithmoides may be climatically restricted to salt-marshes which are coincidentally particularly base-rich.

Within its limited range on salt-marshes, I. crithmoides tends to be more confined to high-marsh occurrences with Elymus pycnanthus in Essex (see Rose 1964, Rose & Géhu 1964).