Microscopy-based inspection of the stems
The surface and cross-sectional characteristics of the stems of both the invasive and native species were observed and imaged via a super resolution system (Liyang Precision Machinery, Chengdu, China). To obtain a high resolution image of the surface structure of stems, twenty multi-focus images with shallow depth of field were taken for each stem, and fused into a higher resolution image using the Zerene Stacker software (Zerene Systems LLC, Richland, WA, USA).