Sentence:  In field infections, the <WSD>enations</WSD> are very small and appear as gray streaks on the backs of the leaves. However, conspicuous <WSD>enations</WSD> appear on plants inoculated and reared in the glasshouse (Lindsten, 1961a; Catherall, 1970). 
Meaning of the word marked with <WSD> tags:  A small outgrowth on the surface of a plant organ.