Its probably a citrus fruit, whose fruits can stay on the tree all year long, and a mandarin, which can also be harvested in winter.

thanks for the help

if Arcimbaldo was a Milanese that indeed should be his experience

The ‘Eureka’ grows year-round and abundantly. This is the common supermarket lemon, also known as “Four Seasons” (Quatre Saisons) because of its ability to produce fruit and flowers together throughout the year. The variety developed in California in the 19th Century from specimens brought to California during the Gold Rush by immigrants from Naples and Sicily.