We are offering Fennel Seeds. Fennel is a perennial herb. It is erect, green, and grows to heights of up to 2.5 m, with hollow stems. Many species in the family apiaceae (formerly umbelliferae) are superficially similar to fennel, and some, such as poison hemlock (see below) are toxic. It is therefore unwise, and potentially extremely dangerous, to use any part of any of these plants as an herb or vegetable unless it can be positively identified as being edible.