1. Flowering shoot with male (a - c) and female (d - f) catkins. - 2. Mature branchlet with fully developed, yet green male (a, b) and female (fruit-) catkins (c, d), and a ripe one (e - i). - 3. Three lobed bracts from (a) outer (abaxial), and (b) inner (adaxial) sides. - 4. Fruit is a winged nutlet. - 5. Seedling with cotyledons and first ordinary leaves. - 6. Winter-branchlet from a young tree furnished with glandular warts. - 7. Winter-branchlet with dormant male catkins (m - o), and the rachis of female catkins after the fruits and bracts fall (p, q, r). 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.