Not as in citrus fruit, but as in a specific kind of lemon, big and lumpy, with a thick rind, and squishy kitchen-sponge-like innards. I now have a double row of them sitting on the kitchen counter. One always picks more than one needs--must be an ancient foraging impulse, like squirreling away pine cones in autumn. Could be why I have so many pairs of glasses. 

We went foraging late afternoon with our extendable picker, good for getting the fruit at the top of the tree, a portable giraffe's neck. There was a concert on campus at 7 pm we recalled, so we collapsed our picker and carried it into the concert hall (this is California, remember, where people arrive on skateboards and all kinds of other things, but it might have been the first time anyone took a fruit picker into the concert hall. The usher looked as us kindly, but anxiously. We handed it over. It has orange claws: we wouldn't have got it onto an airplane either.)

The c18 still life painter I was thinking of is Meléndez, though I didn't find a google image of the painting I thought I had in mind. The one that was closest is not in Madrid but London. It's a little dark.