The genus Phycopeltis (Trentepohliaceae, Chlorophyta) in Ireland: A taxonomic and distributional reassessment

The occurrence of subaerial green algae referable to the genus Phycopeltis (Trentepohliales) has been known in Ireland since 1965. However, the precise identity of Irish populations remains uncles. The taxonomy of Irish Phycopeltis was reinvestigated by light and scanning electron microscopy, using specimens collected over a period of 18 mo. It is concluded that P. arundinacea (= Phyllactidium arundinaceum, described from Algeria) is the only species found in Ireland, and the morphology of Irish specimens is in substantial agreement with the lectotype of P. arundinaceum and previous descriptions of this species. It is proposed that Phycopeltis arundinacea and P. expansa should be retained as separate species, although there is some evidence that the recently described species P. novae-zelandiae may be a synonym of P. expansa. A report of the generitype, P. epiphyron, from Ireland has not been confirmed. Although not currently known from Britain, P. arundinacea is widely distributed in Irish woodlands and other types of habitats characterized by more or less permanent dampness, but it may be more common in the western and south-western regions. Lectotypes are designated for P. arundinacea and P. expansa.