Leaves glossy above: White Mulberry

Leaves matt above: Red & Black Mulberries

Can't find any useful info on distinguishing Red and Black.

Note also that mulberries hybridise freely; some cultivars are hybrid origin (e.g. 'Illinois Everbearing' is hybrid White à Red)

Resin

Unlikely that you've got M.nigra(black).
See linked article below which nicely goes through the traits you can use to differentiate between M.rubra and M.alba.
Hybrids of red & white may be intermediate between the two parent species or more like one or the other.

Here is a link that might be useful: Red & White mulberries in IN

Black mulberry is a comparatively rare and tender variety that would often have to be deliberately sought out and planted before it would be seen on a place.

Not hardy enough to be expected on a cold climate site. Have seen 10 degrees F. minimum temperature indicated before.

Oh. The info about the black mulberry helps, and the article on red and white was really helpful too! I'll post tomorrow when I go outside and id them. If there's leaves yet. I have some seedlings with leaves but I'm not sure about the older trees yet.

This is an interesting subject and I'm confused.
I'm familiar with the red mulberry. It only grows in the forest.
I thought that the white mulberry had the white fruit and thwe Russian mulberry (which seems invasive) has the purple fruit.
Does the white mulberry have both purple and white fruited types?

Yep, White Mulberry fruit can be either white (fairly rare) or purple (more commonly). The white-fruited ones are just a cultivar, like white-fruited cultivars of currants, etc.

Resin

Russian mulberry is white mulberry, Morus alba.

I either have alba or a hybridized plant. I'm very unhappy with this. Especially since I want to plant all natives. So if I go and buy red mulberries, it'll just be wasting my money. It would have been nice to have the native plant.