question about treachery

[Gruesome]

Lets say that you used treachery using a dark ritual...treachery says you can untap up to six lands(i think it's six, i don't remember i don't have it in front of me) and you play it blah blah blah...what happens to the lands...do you untap all of them or does the effect no trigger because the lack of lands.

[Joblin Velder]

You untap as many as you can.

[epeeguy]

You untap as many as you can.

More like, untap as many as you want (you can choose how many to untap).  Regardless of whether you tapped 1 land, or 5 lands to pay for Treachery, the "untap upto 5 lands" is a triggered ability that is triggered when Treachery comes into play (if you played it from your hand).  You can even respond to the Treachery's triggered ability by tapping lands and then the triggered ability can be used to untap them.