Fallacies of Presumption > Suppressed Evidence
The False Dilemma fallacy occurs when an argument offers a false range of choices and requires that you pick one of them. The range is false because there may be other, unstated choices which would only serve to undermine the original argument. If you concede to pick one of those choices, you accept the premise that those choices are indeed the only ones possible. Usually, only two choices are presented, thus the term "False Dilemma"; however, sometimes there are three (trilemma) or more choices offered.
This is sometimes referred to as the "Fallacy of the Excluded Middle" because it can occur as a misapplication of the Law of the Excluded Middle. This "law of logic" stipulates that with any proposition, it must be either true or false; a "middle" option is "excluded". When there are two propositions, and you can demonstrate that either one or the other must logically be true, then it is possible to argue that the falsehood of one logically entails the truth of the other.
That, however, is a tough standard to meet - it can be very difficult to demonstrate that among a given range of statements (whether two or more), one of them absolutely has to be correct. It certainly isn't something which can simply be taken for granted, but this is precisely what the False Dilemma Fallacy tends to do.