(1). “Two hat-shaped” fiber groups emitted green fluorescence can be easily observed, Raphides distribute near the epidermis		D. officinale
(1). “One hat-shaped” fiber groups emitting green fluorescence can be easily observed
	(2). Vascular bundles similar in size, non-specific raphide distribution	D. aphyllum
	(2). Vascular bundles various in size
	(3). Vascular bundles are much bigger in the centre than in the margin of the stem. Raphides distribute near the epidermis and vascular bundles	D. devonianum
	(3). Vascular bundles of different size distribute with no obvious rule. Raphides distribute near the vascular bundle	D. gratiosissimum