From the book Citrus industry (Page 374)
" Clymenia is a remarkable genus (of which only one species is known) is in its general aspect so much like Citrus that it was at first mistaken for a sweet lime. It bears sweetish edible fruits about the size and shape of a sweet lime in color, again like sweet limes. However, Clymenia differs very widely from Citrus in many important taxonomic characters especially in the type of pulp-vesicles. The fruits of Clymenia are about the size of a small orange."
I've seen the tree at the CCPP greenhouse. I obtained a Clymenia seed when Citrus Joe and I visited the CCPP, and germinated it in a 4" pot, but the seedling tree has since died while still being quite young. - Millet