response: Well, you know that fine-bitter herb flavour it has?  It's because of the milky fluid in the thick ribs.
original_response: What about the milky fluid which gives the romaine the typically fine-bitter herb taste.
history: I do not care for romaine lettuce at all. Oh?  Did you know it's tolerant of heat though, unlike most lettuces? I just have never cared for romaine lettuce. Something about the taste. I was not aware it was tolerant of heat. Do you know anything else interesting about it?
knowledge: The thick ribs, especially on the older outer leaves, should have a milky fluid which gives the romaine the typically fine-bitter herb taste.