Riccia cavernosa
Riccia cavernosa, also known as cavernous crystalwort, is a species of liverwort which belongs to the family Ricciaceae.
Description
R. cavernosa develops in rounded rosettes that can reach up to 3 cm in diameter, consisting of numerous lobes that are either oblong or rounded, with their widest part located above the midpoint. The lobes can measure up to 2.5 mm in width and feature a tip that is more or less truncate. Typically, the plants exhibit a yellow-green colour, lacking any reddish pigmentation, and they maintain a yellowish appearance even when dried. The upper surface displays a very short, subtle groove located solely at the tip, along with perforations that extend nearly to the tips of the branches.Discovery
At present, it is estimated that there are 250 species of Riccia, with 152 being widely recognized, while the rest are classified as either 'doubtful' or 'poorly known'.Riccia cavernosa was identified in New Zealand in February 2016, found at the edges of several artificial wetlands created to support the recovery of a threatened native wading bird. That same year, it was also found in Vermont, growing in the cracks of cement walkways in the city of Burlington.