Physcomitrium sphaericum

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Identification notes

A delightful little moss and a rare one too. Finding it means being familiar with its haunts and looking for it in autumn, when its capsules render it conspicuous and when its home on seasonally exposed sediment at the edge of reservoirs and pools can be searched. The best years are probably those in which the reservoir levels have dropped very low in the summer, exposing damp (but not wet) mud for long enough for this short-lived moss to complete its life-cycle before the water rises again.

It’s a member of a fascinating community of bryophytes in this specialised habitat and you may also encounter P. patens, Fossombronia wondraczekii, Riccia sorocarpa, R. huebeneriana, Ephemerum serratum, Pseudephemerum nitidum, Philonotis caespitosa and others.

Read the Field Guide account

Distribution in Great Britain and Ireland

Very local but possibly under-recorded in some districts. Recent surveys of reservoirs in the Brecon Beacons have shown that it is more widespread than previously thought.

View distribution from the BBS Atlas 2014

Similar Species

Other very rare lookalikes include Physcomitrium eurystomum, which has a slightly longer seta than P. sphaericum and distinctly toothed leaf margins and P. readeri, a little-known species with near-black capsules on a short seta (like P. patens).