Populus spp. Height: up to 30 m Stem: grey, dark bark Leaves: mostly heart-shaped or triangular with long petioles Flowers: drooping catkins Fruits/seeds: Capsules containing many small, hairy seeds (wind dispersal) Other: fast-growing deciduous tree that belongs to the willow family Photos: Janina Deutschmann (1,2,3), Martina Gehret (4)