Sentence:  The specificity of staining with * * f was established as follows : * * f specifically stained tumor sections but not sections of healthy sweet clover stems or of <WSD>crown</WSD> gall tumor tissue from sweet clover . 
Meaning of the word marked with <WSD> tags:  a bacterial disease of plants (especially pome and stone fruits and grapes and roses) which forms excrescences on the stem near the ground