PORELLA, in botany; a genus of the natural order of musci, belonging to the cryptogamia class of plants. The antheræ are multilocular, full of natural pores, with an operculum; there is no calyptra, nor pedicle; the capsules contain a powder like those of the other mosses; and their manner of shedding this powder is not by separating into two parts, like those of the felago and lycopodium, but by opening into several holes on all sides.