A and B plants

[Anton]

If any systematic difference between "A" and "B" plants can be detected, this would be very interesting. This would strongly suggest some kind of separation of tasks, like:

one guy described the first set of plants using Currier A, and later he described the second set of plants using Currier B;

OR:

one guy described the first set of plants using Currier A, and later another guy described the second set of plants using Currier B;

OR:

one guy described the first set of plants using Currier A, while another guy at the same time described the second set of plants using Currier B.

I seem the only one here who fails to recognize what is that "horizontal line". Can you please explain with a screenshot?

BTW, are there any systematic differences in hands who drew A and B plants? What do experts say?