Sentence:  Specifically, we ask whether sexual evening primrose plant lineages (Onagraceae) have faster rates of adaptive molecular evolution and altered gene expression of a class I chitinase, a gene implicated in defence against pathogens, than functionally asexual <WSD>evening primrose</WSD> lineages. 
Meaning of the word marked with <WSD> tags:  Any plant of family Onagraceae, the evening primrose family.