Also adding --- the article about gouldiana
here appears to have an issue with description.
"the
three calli are actually a flat 3 striped raised plain" needs some clarification, or maybe even correction.
There's so much information at that site (excellent information) - that it's not surprising that they could have just made mistakes with description at the time of typing.
They probably just meant - there are three calli. Each callus is a flat/thin 'slat' or 'keel'. And - looking from 'above', three red/brown lines - coming together in a V pattern.