remove field label rendering

I am using a custom field type ace editor. the default rendering of fieldset does not conform with my plugin layout. I want remove the column that shows the field label/title.

So when ace editor field is rendered, I want only the editor to show up in one column. So I can put a submit button under it. Field label must be hidden.

Alternatively, if the orientation of label and field can be done vertically (ie. label/title first line, and field under the label) — that would be awesome!