a fungal disease of woody plants that causes localized damage to the bark

an ulceration (especially of the lips or lining of the mouth)

a pernicious and malign influence that is hard to get rid of

become infected with a canker

infect with a canker

North American evergreen fern having pinnate leaves and dense clusters of lance-shaped fronds

an ulceration (especially of the lips or lining of the mouth)

having an ulcer or canker

herb of northeastern North America having drooping clusters of yellowish-white flowers; sometimes placed in genus Prenanthes

green caterpillar of a geometrid moth; pest of various fruit and shade trees