Regnellidium References Regnellidium fern genus Ask Anything Homework Help Written by The Information Architects of Encyclopaedia Britannica The Information Architects maintain a master list of the topics included in the corpus of Encyclopædia Britannica, and create and manage the relationships between them. The Information Architects of Encyclopaedia Britannica Britannica AI Ask Anything Learn about this topic in these articles: MarsileaceaeRegnellidium, with one species, has leaves with two leaflets and is confined to southern portions of Brazil and Argentina. Read MoreRegnellidium, with one species, has leaves with two leaflets and is confined to southern portions of Brazil and Argentina. Read Morefern/ Annotated classification(waterclover), Pilularia (pillwort), and Regnellidium—with about 75 species found nearly worldwide. Order Cyatheales (tree ferns) Family Cyatheaceae (scaly tree ferns) Stems erect and mostly trunklike (to 25 metres, [82 feet]) Read More(waterclover), Pilularia (pillwort), and Regnellidium—with about 75 species found nearly worldwide. Order Cyatheales (tree ferns) Family Cyatheaceae (scaly tree ferns) Stems erect and mostly trunklike (to 25 metres, [82 feet]) Read More