When posting a question using an iPad, the richtext box icons are missing.
P.s.: Also the similar questions div can't be scrolled, but this has been noted earlier.
This is by design; we disable the WMD editor on iPhone and iPad because it behaves poorly there.
There is a backtick key, though this only showed up in recently (maybe with iOS 4?). If you tap and hold the apostrophe key, you'll see a little menu pop up with alternate characters (for example, tapping and holding the "u" key shows: ú, ù, ü, û, u). One of the alternate characters is the backtick (`).
Here's what it looks like on my iPhone: