With the new academic year it is time to change the background image, mostly because all kinds of titles were not visible on the old 'pollen' background.
The image is taken from wikimedia commons: https://commons.wikimedia.org/wiki/File:Plant_stem_%28255_06%29_Cross-section_of_stem_of_Aristolochia.jpg
Since these are cells from a stem, I guess they qualify as stem cells ;)
Henk