The stems of Dendrobium officinale Kimura et Migo, named Tie-pi-shi-hu,
is one of the most endangered and precious species in China. Because of its various
pharmacodynamic effects, D. officinale is widely recognized as a high-quality health food
in China and other countries in south and south-east Asia. With the rising interest of
D. officinale, its products have a high price due to a limited supply. This high price has led
to the proliferation of adulterants in the market. To ensure the safe use of D. officinale, a
fast and convenient method combining normal and fluorescence microscopy was applied
in the present study to distinguish D. officinale from three commonly used adulterants
including Zi-pi-shi-hu (D. devonianum), Shui-cao-shi-hu (D. aphyllum), Guang-jie-shi-hu
(D. gratiosissimum). The result demonstrated that D. officinale could be identified by the
characteristic “two hat-shaped” vascular bundle sheath observed under the fluorescence
microscopy and the distribution of raphides under normal light microscopy. The other three
adulterants could be discriminated by the vascular bundle differences and the distribution of
raphides under normal light microscopy. This work indicated that combination of normal light
and fluorescence microscopy is a fast and efficient technique to scientifically distinguish
D. officinale from the commonly confused species.