All the sorbus that I am familiar with have clusters of fruit and compound leaves. Could well be a crataegus, but if so, it should have thorns, and the fruit is usually a pome (like an apple or pear), not a berry - for what it's worth, this fruit looks like a pome to me. If the fruit is a pome then it will have seeds in many separate chambers. However, Crataegus monogyna has a single seed. Most dark-leaved trees in the rose family are cherry cultivars, which prolifically produce green-leaved suckers, but this tree lacks glands on the petioles. I've attached a Crataegus key. Here is a link that might be useful: Crataegus key

One of the distinguishing characteristics of the Oroblanco (and about the only way you can tell them apart from their genetic sibling, the Melogold), is a pronounced "dimple" or indentation on the blossom end of the fruit (see link below). To distinguish it from a pommelo, all pommelos are VERY seedy and have a very tough center core. And, they are really big, huge fruits. Plus, most pummelos are sweeter than the Oroblanco is, as it has grapefruit in its background. Pummelos are very sweet, no bitterness. The Oroblanco is sweeter than a grapefruit, but still a little more bitter than a pommelo. By the look and size of the fruit in your photo (can't quite see the bottom), it appears to be an Oroblanco. Patty S. Here is a link that might be useful: UC Riverside Citrus Variety Collection: Oroblanco

I suppose it probably is Ruellia brittoniana as it does very closely resemble it in some ways but most of the pictures I've googled are close-ups and the leaves seem to be more narrow and more abundant than the ones in question. The ones that I've seen seem more "airy" than the pictures...not so many and so so close together. Also, the color doesn't come across quite the same in the pictures but I suppose that could be because of growing conditions. Let me know what you think. Puppyscruff, did you grow yours from seed? It's not hardy here, is it? Any way I could see a picture of yours for comparison? Thank you. I really appreciate your help. Love strikes my fickle heart yet again!

Midas Touch and Henry Fonda are popular yellow J&P HTs. Henry Fonda is winter tender--we lost ours in a mild Z6 winter.