mustard tree

(noun) evergreen South American shrub naturalized in United States; occasionally responsible for poisoning livestock. Synonyms: tree tobacco, mustard tree, Nicotiana glauca.

(noun) glabrous or pubescent evergreen shrub or tree of the genus Salvadora; twigs are fibrous and in some parts of the world are bound together in clusters and used as a toothbrush; shoots are used as camel fodder; plant ash provides salt. Synonyms: toothbrush tree, mustard tree, Salvadora persica.