At least, it’s ripe by my standard: it fell off the tree during the night. By this point the fruit usually smells “lemony,” but although it looks ripe I can’t smell anything. This fruit has been growing since last winter. It’s the same fruit captioned “new lemon fruit” in the last photo of my post from April and “large lemon fruit” in the first photo of my post from a month ago.
There was a broken branch on the ground as well as the lemon. This small branch was growing just beyond where the lemon was attached. I think that when the (rather heavy) lemon fell off, the branch sprang up, the end brushed the nearby Surinam cherry tree, and this part snapped off.
There are three small lemon fruits growing on the tree that may ripen this winter. Several new fruits have formed as well, but many of these will probably drop off. There is one flower on the tree now.