This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Deciduous shrubs or small trees with bitter bark, usually alternate trifoliolate or pinnate leaves with pellucid dots, cymose inconspicuous yellowish green flowers, and orbicular winged fruits. Flowers polygamous. Calyx 4- or 5-partite, lobes imbricate. Petals 4 or 5, much longer than the calyx. Stamens 4 or 5. Ovary 2- or 3-celled, with 2 ovules in each cell. There are six species, from temperate North America. is the Greek name of Ulmus campestris, which like this has winged fruits.
1. P. trifoliata. Hop-tree. - A small tree of no special merit, with trifoliolate glabrous yellowish green leaves on long-petioles; leaflets ovate, obscurely crenate. The leaves and fruits when bruised emit a powerful odour resembling hops. There is a variegated variety.
Phellodendron Amurense is a small hardy tree from North-eastern Asia, with opposite or alternate unequally pinnate eglandular leaves and inconspicuous dioecious flowers.