 3,4,8-Trimethoxyphenanthrene-2,5-diol is one of the 17 phenanthrenes found in the extract of the stems of the orchid "Dendrobium nobile".From the stems of the orchid "Flickingeria fimbriata", three phenanthrenes can be isolated.The structures are 2,5-dihydroxy-4,9,10-trimethoxyphenanthrene, 2,5-dihydroxy-4-methoxyphenanthrene and 2,5,9-trihydroxy-4-methoxy-9,10-dihydrophenanthrene.