Arum is a genus of flowering plants in the family Araceae. They are native to Europe, northern Africa, and western and central Asia, with the highest species diversity in the Mediterranean region. Frequently called arum lilies, they are not closely related to the true lilies Lilium. Plants in the closely related genus Zantedeschia are also called 'arum lilies'.
They are rhizomatous, herbaceous perennial plants growing to 20–60 cm (7.9–23.6 in) tall, with sagittate (arrowhead-shaped) leaves 10–55 cm (3.9–21.7 in) long. The flowers are produced in a spadix, surrounded by a 10–40 cm (3.9–15.7 in) long, distinctively coloured spathe, which may be white, yellow, brown, or purple. Some species are scented, others not. The fruit is a cluster of bright orange or red berries.
All parts of the plants, including the berries, are poisonous as they contain needle-shaped crystals of calcium oxalate. In spite of this, the plant has a history of culinary use among Arab peasants in Palestine who leached the toxins from the plant before the leaves were consumed.
The genus name is the Latinized form of the Greek name for these plants, aron.
Inflorescence and pollination
Historical model of the inner part of the inflorescence, the spadix with the flowers and ring of small hairs. Botanical Museum Greifswald.
The flowers are borne on a poker-shaped inflorescence called a spadix, which is partially enclosed in a spathe or leaf-like hood of varying colour. The flowers are hidden from sight, clustered at the base of the spadix with a ring of female flowers at the bottom and a ring of male flowers above them.
Above the male flowers is a ring of hairs forming an insect trap. The insects are trapped beneath the ring of hairs and are dusted with pollen by the male flowers before escaping and carrying the pollen to the spadices of other plants, where they pollinate the female flowers. Once the plant is pollinated, the small hairs wither away and the trapped insects are released.
