My Favourite Marchantians

Day 273: It is argued that Marchantia alpestris should be treated as a separate species from M. polymorpha, a notorious pest in greenhouses. The differences are subtle, but more importantly, M. alpestris does not form extensive monocultures where it occurs naturally. The spread of this liverwort is kept in check by mosses, lichens and the harsh environment surrounding it, a factor which confines it to the shadier and damper areas of the subalpine ecology. It colonizes in areas scarified by fire and may be abundant until such time as other bryophytes and vascular plants get a toe-hold, but for the most part, only survives en masse in the mats of moss along the margins of small streams and seeps. The "umbrellas" shown in this photo are the male reproductive structures (antheridia).