I've always used the word (spelling) homogenous to describe things of similar nature. However, when I started university I heard everyone use the word homogeneous (pronounced "homo genius" or "homo jean us").
This article suggests that homogenous has evolved from having a specific meaning in biology (having a similar structure due to common ancestry) to becoming the most common spelling of the word, and that only "careful writers" try to keep these two spellings separate.
However, The Oxford Guide to English Usage says that homogenous is a "frequent error for homogeneous", and my browser agrees, declaring every instance of homogenous in this question a spelling error.
In my own opinion, homogeneous sounds pretty strange because of the stress on "genius" despite having nothing to do with intelligence.
What is the current status on these two words? What is their relationship, and what is correct usage?