Four Species (Hebrew:ארבעת המינים) are plants mentioned in the Torah as being relevant to Sukkot.
The Four Species are:
• Lulav (לולב) – a ripe, green, closed frond from a date palm tree
• Hadass (הדס) – boughs with leaves from the myrtle tree
• Aravah (ערבה) – branches with leaves from the willow tree
• Etrog (אתרוג) – the fruit of a citron tree
During Sukkot the four species are brought together in the form of an etrog and the lulav .The Four Species are waved together along with special blessings as part of the synagogue service during Sukkot. They can also be waved at home or near the sukkah. Traditionally the Four Species are not waved on Shabbat because doing so would violate the prohibition against carrying things during the Shabbat.
This mitzvah is derived from the Book of Leviticus: “And you shall take for yourself on the first day the fruit of goodly trees, branches of palm trees, and boughs of thick trees, and willows of the brook” (Leviticus 23:40).