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.
Cryptanthus Cryptanthus is a genus in the botanical family Bromeliaceae, subfamily Bromelioideae. The genus name is from the Greek “cryptos” (hidden) and “anthos” (flower). This genus has two recognized subgenera: the type subgenus and "Hoplocryptanthus" . All species of this genus are endemic to Brazil. The common name for any "Cryptanthus" is "Earth Star".