I guess anyone who knows much about childbirth (and I know less than most) can guess that anything lactescent is prone to producing milk. So it may seem odd (and, frankly a huge relief) that there is a photo of lettuces.
The odd choice is because lettuces are one of the many plants that, if cut, seep milky sap or juice. In fact lettuces are, botanically speaking Lactuca sativa which obviously has its origins in lactea (or milk) and the sativa bit means cultivated or domestic.
Other lactescent plants include dandelions, euphorbia, ficus and some campanulas.
The Romans called the Milky Way the Via lactea but our word Galaxy comes from the Greek for milk – Gala – as in ornithogalum – bird’s milk (for some reason that must had made sense to someone! )