Fertile flowers in a short catkin, head, or strobile. [Urticaceæ], [461]
Fertile flowers single or clustered; sterile in slender catkins (except in Fagus).
Leaves pinnate; fertile flowers and fruit naked. [Juglandaceæ], [467]
Leaves simple; fertile flowers 1–3 in an involucre or cup. [Cupuliferæ], [470]
2. Both sterile and fertile flowers in catkins or catkin-like heads.
Ovary and pod 2-celled, many-seeded. [Liquidambar], in [Hamamelideæ], [180]
Ovary and pod 1-celled, many-seeded; seeds furnished with a downy tuft at one end. [Salicaceæ], [480]
Ovary 1–2-celled, only one ovule in each cell; fruit 1-seeded.
Parasitic on trees; fruit a berry. [Loranthaceæ], [449]
Trees or shrubs, not parasitic.