1. Branchlet with young shoot, male catkins (a - c) and female inflorescences (d), as well as a one year old (immature) fruit covered by the cup-like involucre (e). - 2. Branchlet with developed shoots and almost ripe - two years old - fruits (nuts, acorns) with the cup; fruits are developing with very short stalk, cups are equipped with long, linear, downy scales (bracts). - 3. Ripe acorn. - 4. Empty cup. - 5. Winter-branchlet; buds are furnished with long, linear, persistent stipules. One year old (immature) acorn (a) in winter. After Hempel & Wilhelm, 1889. Photos and explanations from the book: Zelimir Borzan. "Tree and Shrub Names in Latin, Croatian, English, and German, with synonyms", University of Zagreb, 2001.