Aneura pinguis
Marchantiophyta
Aneura pinguis (Aneuraceae)
Greasewort
Infrequent
Distinguishing Features
Aneura pinguis is found across a diversity of habitats, from rocks to bogs, where its deep green and relatively unbranched thallus creeps among other bryophytes. The thallus can grow between 2-5 cm long and 2-6 mm wide, having a characteristic greasy texture when its fresh tissues are rubbed. The thallus, though thickest in the center (10-to-20 cells thick), lacks an obvious midrib and tapers gradually towards its margins (1-to-3 cells thick). Under the microscope, oil bodies are colourless and abundant (6-to-20 per cell). The male and female plants are seperate; sporophytes, when present, emerge from the underside of the plant.
Similar species
Because of its amorphous and thick thallus, A. pinguis could be mistaken for many other bryophytes. It has a thallus not dissimilair to the hornworts Anthoceros and Phaeoceros, but those two genera have thalli that form brached rosettes and bear pyrenoids in their cells, large photosynthetic apparati that are absent in the mostly linear thalli of Aneura. Species of Pellia are similar in form, but have a more pronounced midrib and lack the turpentine smell of fresh Aneura. It should also be noted that sporophytes are produced along the upper surface in the former but emerge from the underside of the thallus in the latter. Species or Riccardia are narrower (thallus segments < 2 mm wide) and their surficial cells have fewer oil bodies.
Habitat
Moist to wet mineral soil, humus, bogs, fens, swamps, peatlands, streambanks, shorelines, decayed logs, seepage areas, cliffs, boulders, rock outcrops, ledges, waterfall spray zones, and disturbed areas in the lowland, montane, and subalpine zones;
Associated species
Sphagnum sp.