The geographical distribution of Racomitrium lanuginosum is governed by (i) its susceptibility to desiccation (tufts of the moss may become physiologically inactive below 95% relative humidity; Tallis, 1964), so that its growth is inhibited by infrequent precipitation/low humidity, and (ii) a preference for colder climates, optimum growth occurring at temperatures of 8–10o C
It also doesn't like a permanently high water table, and grows at 5-15mm per year (vulnerable to competition)
The main stems of R. lanuginosum bear elongated lateral branches, which are often grouped into definite ‘branch zones’. Lateral branches are formed during late May, June, and July and some of these will elongate further to become new main stems.Normally only one branch zone is produced each year, so that the distance between interfascicular zones can be used as an approximate, innate marker of annual growth.
Initially I thought there was only one small patch at Cullaloe LNR, but on investigating in the sunshine yesterday there is a healthy collection of small colonies present.
|R.lanuginosum colony at Cullaloe LNR|