The bulliform cells were situated in groove of upper epidermis facing the main vein.
Condyloma accuminatum has prominent koilocytosis in the upper epidermis that is not found in verruciform xanthoma.
The upper epidermis, palisade tissues and leaves are all thinner, so the leaves are more tender, and its yield is 8% higher;
There are 2-3 layers of long-column-shaped palisade tissue under the upper epidermis, and there are a great number of mechanical tissues which made up of vascular bundle sheath .
