Yemenite Citron - Etrog HaCushi

Etrog haCushi (Hebrew: אֶתְרוֹג הַכּוּשִׁי‎) is mentioned in the Mishnah as well as in both the Babylonian (Succa 36a) and the Jerusalem Talmud (Succa 3:6). The most common interpretation is that the Biblical Cush refers to Ethiopia, and therefor Etrog haKuschi should also refer to something which could be called the Ethiopian citron.

The Ethiopian Jews did not follow the mitzva of four species, even though they did anticipate the Sukkot festival, as well as the rest of the Jewish ethnic divisions. This may have been due to their lack of ability to procure the species. Some believe that this is due to some Karaite influence, whose biblical interpretation indicates that the four species are only used as roofing for a sukkah (the S'chach), and not for a separate waving ritual.

However, the Yemenite citron is available in Ethiopia and its markets, where it is sold for consumption. According to Erich Isaac, the late researcher of citrus distribution, the Yemenite citron is synonymous with the Ethiopian citron as a result of Ethiopian rule of Yemen in the past.