Lunularia cruciata
Marchantiophyta
Lunularia cruciata (Lunulariaceae)
Locally weed
Distinguishing Features
Lunularia cruciata is a weedy species typical of garden margins that reaches the limits of its tolerance in south coastal British Columbia. It is a complex thalloid liverwort with short, overlapping segments to about 1cm wide and 3 cm long that grow prostrate over fine soils and almost always have semicircular cups on the upper surface that house and disperse asexual spores ("gemmae cups", see photo). Sporophytes have not been observed in regional material, but in the event that the gemmae cups are absent, attention should be paid to the simple pores on the thallus and the brown colour of the scales on its underside.
Similar species
When gemmae cups are present, L. cruciata can only be mistaken for Marchantia polymorpha, but in that species the cups are circular, not semicircular or crescent shaped as they are in Lunularia. The weedy habitat is a good clue for plants of L. cruciata that lack gemmae cups, but the simple pores are a good backup feature: the presence of simple pores distinguishes Lunularia from species of Marchantia, which have compound pores, while the presence of brown scales on the underside of L. cruciata seperate it from other complex thalloid genera with simple pores (Mannia, Reboulia, Clevea, Targionia), where the scales are purple or white.
Habitat
Associated species