Identification notes
Let’s be straight about this – O. perssonii is not a liverwort that will be spotted without careful searching of the rather specific (and rare) microhabitat it prefers. It is very, very small and even a relatively large patch of shoots will always just look like a smudge of algae from even a few centimetres away.
Its pale green shoots are found on clayey chalk or rarely, soft limestone, in disturbed but not fast-eroding ground. Barish tracksides and ruts are particularly favoured spots, where you will typically find it with Mesoptychia turbinata (usually dark green to blackish in colour), Dicranella howei, Seligeria calcarea or S. calycina. The trick to finding O. perssonii is finding such places and then visually scanning the substrate for small pale green smudges. One you’ve honed in on some with a hand-lens, it’s easy to identify because some shoots will always have tell-tale clusters of brown gemmae at their tips.
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