Sentence:  [T]he stems of the culinary <WSD>rhubarb</WSD> plant ("Rheum palmatum") are used in stewing, jams and in tarts and pies. <WSD>Rhubarb</WSD> roots were a traditional purgative and the leaves of the <WSD>rhubarb</WSD> plant are rich in oxalic acid. This causes irritation of the mouth and the oesophagus. Ingestion of <WSD>rhubarb</WSD> leaves induces vomiting and abdominal pains. 
Meaning of the word marked with <WSD> tags:  Any plant of the genus "Rheum", especially (noshow=1), having large leaves and long green or reddish acidic leafstalks that are edible, in particular when cooked (although the leaves are mildly poisonous).