Cotyledons and the Plant Embryo

Hello everyone!

Been getting a lot of help on this forum; hope you all don't mind another question!

I was reading about mature seeds, but have a bit of trouble understanding part of the plant organization. The majority of pictures I have seen of dicots outline the epicotyl, hypocotyl, and cotyledons; however, in the pictures it seems that the cotyledons are not attached to the embryo.

Epicotyl: part of embryo above where the cotyledons attach
Hypocotyl: part of embryo below where the cotyledons attach

Please take a look at the image below, which is pretty standard, I've looked at many such pictures, and none seem to show the cotyledons actually being attached to the embryo. Is it separate or is it physically attached to the embryo's body?

Also, would the coleoptile/coleorhiza of grass monocots be considered part of the cotyledon?

Thank you!