Publication: Sp. Pl. 2: 998. 1753.
Origin: Introduced from Europe
selected vouchers: WTU
Notes: FNA3: "Corylus avellana is widely grown as an ornamental shrub in temperate North America, and it sometimes persists following cultivation, although it seldom becomes established.
Corylus avellana is similar to C . americana in habit, leaves, and fruit characteristics, although it becomes much larger. If fruits are present, the two species can be distinguished by the involucre, which is shorter than the nut in C . avellana . The best technical character for separating these species in the absence of fruits is the length of the peduncles of the staminate catkins (which are formed during the summer prior to the season of blooming)."