In my plant reproduction book there are two distinct definitions for these two terms, but when I read them I found out that they are very much alike that I was confused and couldn't catch the difference between them. I searched on Google and found this on wikidiff:
As adjectives the difference between homothallic and monoecious is that homothallic is (of some algae and fungi) producing male and female reproductive structures in the same plant while monoecious is (botany) that has male and female reproductive organs on the same individual plant (rather than on separate individuals).
But, still, isn't this the same sentence using another words? Thanks for answering.