ESSEX   BOTANY   AND   MYCOLOGY  GROUPS 

This taxon is very close to R. chamedryfolia, and it is only since Little,1968 that the most useful oil-body character has been available for separation. Both are also sometimes mistaken for small forms of male Pellia endiviifolia, which however has 5-20 oil bodies per cell as opposed to 1-2. R.multifida is generally more regularly pinnate in its branching, and the ultimate segments tend to be parallel sided, whereas in R. chamedryfolia the segments are generally slightly expanded at the tips. The margins in R. multifida are usually obviously translucent and turned slightly downwards, and the 1-3 rows of unistratose marginal cells, together with the epidermal cells,  lack oil bodies, whereas in R. chamedyfolia the margins are not noticeably translucent or turned down and all the cells of the thallus have oil bodies. A further character is that the upper epidermal cells in R. multifida are noticeably convex whereas they tend to be flat in R. chamedryfolia, most easily observed by looking at the edges of the ultimate segments from above.  Both tend to live in permanently wet sites, in a wide range of habitats, but in eastern England R. multifida is rare, and appears to prefer really boggy conditions that are slightly acid.