Parting of the sensory

This week's lab covers primary and secondary growth in plants. The students are supposed to be able to identify the different types of cells and tissues in the non-reproductive plant organs. A lot of that comes from looking at prepared slides. Yesterday I had a student who was struggling with how to tell the difference between xylem and phloem on this slide:


Me: The xylem is stained purple, and the phloem is stained blue.
Him: I can't differentiate between those colors. I'm colorblind.
Me: In that case, the xylem consists of those big cells in the middle that kind of make an X. The phloem are the smaller cells surrounding that.
Him: Ok, that helps.

A little while later:

Him: So, am I pointing at the phloem here on this stem cross section?

Me: No. You're pointing at the fiber bundle cap. The phloem's blue.
Him: That doesn't help. Remember?
Me: Oh yeah. Sorry.

A little while later:

Him: I can't see that either.
Me: You know, this would be so much easier to explain to you if you weren't colorblind.
Him: Are you making fun of my disability?
Me: Only a little, and only because I know you can take it.
Him: That's it! I'm going to go on ratemyprofessor and tell people to avoid you. I'm going to write: He likes to make fun of people with disabilities. Do not take this guy if you are in a wheelchair.