How does 'to partake of' mean 'be characterized by'?

Solution 1:

Well, "partake of" generally means "to take part in".

So, if you "partake of" a certain quality, that means you take part in a certain quality. Here's an example:

Many recent books partake of Faulkner's wordiness.

So, each new book "joins in" with the quality, and thus becomes part of the group (wordy books) that is characterized by it.