Araceae (Arum lily family)

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Monocotyledons > Order: Alismatales

There are 106 genera and about 4025 species (tropics and subtropics plus some species in temperate regions; especially diverse in New World tropics), with nine genera and 21 species indigenous to southern Africa. In addition one genus and one species is naturalised, and 18 genera and 44 species are cultivated in the region. The Lemnaceae has been synonymised with the Araceae and previous members of this family are included here. They are all aquatic plants with small floating leaves and tiny flowers.

Genera indigenous to southern Africa

List from Singh (2000).

Amorphophallus About 100 species, found throughout the Old World tropics, with one species, Amorphophallus abyssinicus, indigenous to southern Africa (in Caprivi Strip, Namibia with distribution extending northwards).
Gonatopus Five species, found in tropical and southern subtropical Africa, with 2 species occurring in southern Africa (Mpumalanga and northern KwaZulu-Natal).
Stylochaeton About 15 species, found in tropical and southern subtropical Africa, with 1 species, Stylochaeton natalensis, occurring in southern Africa (Mpumalanga and KwaZulu-Natal).
Zamioculcas The only species is Zamioculcas zamiifolia, found in eastern and southeastern tropical Africa, extending as far south as norther KwaZulu-Natal.
Zantedeschia There are eight species, all of which are indigenous to southern Africa.

Genera previously included in the Lemnaceae

List from Glen (2000).

Lemna There are 13 species worldwide of which three are indigenous in southern Africa.
Spirodela Two of the three species are native to southern Africa.
Wolffia The only species is Zamioculcas zamiifolia, found in eastern and southeastern tropical Africa, extending as far south as norther KwaZulu-Natal.
Wolffiella There are nine species worldwide, of which two are indigenous in southern Africa.

Genera naturalised in southern Africa

* Pistia

Only 1 species, the Water Lettuce Pistia stratiotes, found worldwide in warm regions, and a naturalised weed in southern Africa. It is a declared Category 1 invasive plant in South Africa.

Other genera, cultivated in southern Africa

Based on Glen (2002) and Brickell (1996). Number of species recorded as being cultivated in southern Africa is given in square brackets. This list excludes genera with naturalised species to southern Africa, which have already been listed above. Acorus was previously placed in the Araceae but now is placed in its own order (Acorales) and family (Acoraceae).

Aglaonema About 20 species, indigenous to the tropical forests of Asia. Grown particularly as pot plants [3 cultivated species]
Alocasia About 70 species, found in tropical forests and damp, shady places in S and SE Asia. [6 cultivated species]
Anthurium About 700-900 species found in wet mountain forests of tropical and subtropical North and South America. [5 cultivated species]
Arisaema About 150 species, from moist woodland and rocky wasteland in Asia and North America.
Arisarum Three species, found in Europe. [1 cultivated species]
Arum About 26 species, distributed in S Europe, N Africa and W Asia to the W Himalayas [2 cultivated species]
Caladium Seven species, from tropical South America [1 cultivated species]
Colocasia (Taro genus) Six species, found in tropical Asia where one species in particular, Colocasia esculenta (Taro, Cocoyam, or in Zulu 'Amadumbe'), is grown as a staple food. This species is also grown for food in southern Africa and was probably introduced here by Portuguese traders before 1500 [1 cultivated species].
Dieffenbachia About 30 species, found in tropical forests of North and South America as well as in the West Indies [3 cultivated species]
Dracunculus (Dragon Arum) Three species, native to the Mediterranean, Madeira and the Canary Islands. [1 cultivated species]
Epipremnum Eight species, all root-clinging climbers, native from S.E. Asia through to the west Pacific [2 cultivated species]
Monstera (Delicious Monster) A total of 22 species, native to the Americas. The Delicious Monster Monstera deliciosa is widely cultivated in gardens and is so called because the ripe fruit can be eaten. Eating the unripe fruit is not recommended because it contains calcium oxalate crystals. [1 cultivated species]
Montrichardia A single species, Montrichardia linifera, native to northern South America.
Philodendron About 500 species, native to the Americas, mainly in rain forest. [8 cultivated species]
Sauromatum Two species, native to the Himalayas and East and West Africa. Inflorescences have a foetid smell. The Voodoo Lily Sauromatum venosum is the species most commonly cultivated in gardens. [1 cultivated species]
Spathiphyllum A total of 36 species, native to tropical regions of Indonesia, the Philippines and the Americas. Often grown as indoor plants. [3 cultivated species]
Syngonium About 33 species, native to Central and South America. [2 cultivated species]
Typhonium About 30 species, native to SE Asia. [2 cultivated species]

Characteristics (excluding genera previously in Lemnaceae)

Flowers

The following characteristics distinguish members of the Araceae from other families:

they have an inflorescence termed a spadix consisting of small closely packed flowers arranged round a swollen, fleshy column.
the spadix has a (usually) large, petal-like bract wrapped round its base termed a spathe.

Some species have separate male and female (i.e. unisexual) flowers (e.g. Arum Lily Zantedeschia aethiopica) while in other species male and female parts are combined in one (i.e. bisexual) flower (e.g. Anthurium, Monstera). In species with unisexual flowers, the male flowers are at the top and the female flowers at the bottom of the spadix.

Leaves

simple or compound
venation parallel, pinnate or palmate
the petiole of the leaf has a membranous sheathing base.
the leaves of the Delicious Monster Monstera deliciosa have large holes in them.

Roots

Adventious

Fruit

A berry, i.e. a fleshy fruit without a stony layer containing one to many seeds.

Publications

Bogner, J. & Nicolson, D.H. 1991. A revised classification of Araceae with dichotomous keys. Willdenowia 21: 35-50.
Brickell, C. (ed.) 1996. The Royal Horticultural Society A-Z Encyclopedia of Garden Plants. Dorling Kindersley, London.
Glen, R.P. 2000. Lemanceae. In: Seed Plants of Southern Africa (ed. O.A. Leistner). Strelitzia 10: 640-641. National Botanical Institute, Pretoria.
Glen, H.F. 2002. Cultivated Plants of Southern Africa. Jacana, Johannesburg.
Mayo, S.J. 1985. Araceae. Flora of Tropical East Africa: 1-71.
Mayo, S.J., Bogner, J. & Boyce, P.C. 1997. The Genera of Araceae. Royal Botanic Gardens, Kew.
Walters, S.M. et al. (eds). Araceae. In: European Garden Flora 2: 75-112.
Singh, Y. 2000. Araceae. In: Seed Plants of Southern Africa (ed. O.A. Leistner). Strelitzia 10: 578-580. National Botanical Institute, Pretoria.