I am not sure if this may be of help, but interestingly there seems to be very little information in the field of plant biometrics. Weird!
Plant species biometric using feature hierarchies (2008) Abstract
Biometric identification is a pattern recognition based classification system that recognizes an individual by determining its authenticity using a specific physiological or behavioural characteristic (biometric).
In contrast to number of commercially available biometric systems for human recognition in the market today, there is no such a biometric system for plant recognition, even though they have many characteristics that are uniquely identifiable at a species level.
The goal of the study was to develop a plant species biometric using both global and local features of leaf images. In recent years, various approaches have been proposed for characterizing leaf images. Most of them were based on a global representation of leaf peripheral with Fourier descriptors, polygonal approximations and centroid-contour distance curve.
One biometric that is common to all Eukaryotic life is the presence of microtubules in the cytoskeleton and cytoplasm in every cell of every living organism. Trillions of nanoscale dipolar coils that act as electrochemical potentiometers.
In plants they may be instrumental in photosynthesis.
It is "the little engine that could". Thread to follow as soon as I have a good generalized introductory opening post.