18006
Essential oils were obtained by hydrodistillation of different parts ( flower heads , leaves , stems , and roots ) of C . sumatrensis plants , which were collected in autumn ( November 2007 ) at the flowering stage in the area of Monastir , Tunisia .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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