are Cladanthus and Oxydendrum both plant genus ?
Oxydendrum Sourwood or sorrel tree, Oxydendrum arboreum, is the sole species in the genus Oxydendrum, in the family Ericaceae. It is native to eastern North America, from southern Pennsylvania south to northwest Florida and west to southern Illinois; it is most common in the lower chain of the Appalachian Mountains. The tree is frequently seen as a component of oak-heath forests.
Echinodorus Echinodorus (burhead or Amazon sword plant) is a genus of plants in the family Alismataceae and distributed in the Western Hemisphere from the central United States to Argentina. Its scientific name is derived from Ancient Greek "echius" – rough husk, and "doros" – leathern bottle, alluding to ovaries, which in some species are armed with persistent styles, forming prickly head of fruit. Some of the species are commonly cultivated in artificial aquatic habitats.