We have what seems like a mature orange tree but can’t figure out what kind. This is in Northern California. The fruit has been present at least since last summer (when we moved in), probably since last spring. Just now starting to ripen with most fruit orange, some still green (the green ones are very large, grapefruit sized).
I believe the tree has had not the best care (so not sure if this is a low nutrient etc crop). The peel is very thick and (besides the stiffness) pulls apart from the slices easily. The slices pull apart from each other easily. The peel is bumpy, especially on the end that attached to branch. No seeds. No apparent navel. Slices are fairly meaty especially when compared to mandarins. Juice does taste similar to a mandarin, with a strong sweet/tangy flavor.