this is a section through the stem of Urtica, stained with a dye with high affinity for lignified cell walls
Nikon Ni-U microscope and Nikon DS-Fi3 camera
Transverse section through the stem of Verbena bonariensis
left is brightfield, right is the same unstained section viewed using the PN31001 DAPI LP filters
red shows the autofluorescence of chlorophyll
Blue shows autofluorescence of lignin