''Arum'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s in the family
Araceae
The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). Also ...
,
native
Native may refer to:
People
* Jus soli, citizenship by right of birth
* Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory
** Native Americans (disambiguation)
In arts and entert ...
to Europe, northern Africa, and western and central Asia, with the highest species diversity in the Mediterranean region.
[Kew World Checklist of Selected Plant Families]
/ref> Frequently called arum lilies, they are not closely related to the true lilies ''Lilium
''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. M ...
''. Plants in closely related ''Zantedeschia
''Zantedeschia'' is a genus of eight species of herbaceous, perennial, flowering plants in the family Araceae, native to southern Africa from South Africa north to Malawi. The genus has been introduced on all continents except Antarctica. Com ...
'' are also called "arum lilies".
They are rhizomatous
In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...
, herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of t ...
perennial plant
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...
s growing to 20–60 cm tall, with sagittate (arrowhead-shaped) leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
10–55 cm long. The flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s are produced in a spadix, surrounded by a 10–40 cm long, distinctively coloured spathe
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
, which may be white, yellow, brown, or purple. Some species are scented, others not. The fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
is a cluster of bright orange or red berries
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...
.
All parts of the plants, including the berries, are poisonous, containing calcium oxalate
Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate ...
as raphides
Raphides (pronounced /ˈræfɪˌdiz/, singular raphide /ˈreɪfʌɪd/ or raphis) are needle-shaped crystals of calcium oxalate monohydrate ( prismatic monoclinic crystals) or calcium carbonate as aragonite ( dipyramidal orthorhombic crystals), ...
. In spite of this, the plant has a history of culinary use among Arab peasants in Palestine
__NOTOC__
Palestine may refer to:
* State of Palestine, a state in Western Asia
* Palestine (region), a geographic region in Western Asia
* Palestinian territories, territories occupied by Israel since 1967, namely the West Bank (including East ...
who practised leaching 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
The flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s are borne on a poker-shaped inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
called a spadix, which is partially enclosed in a spathe
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
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
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
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.
After the inflorescence opens, the spadix heats up well above ambient temperature, due to a phenomenon called thermogenesis
Thermogenesis is the process of heat production in organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily (''Sauromatum venosum''), and the giant wate ...
. This is caused by the rapid consumption of starch in cyanide insensitive respiration
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms.
In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a ...
, which is biochemically different from the respiration normally found in plants. The heat is used to vaporize odour components, which in species with short "flower-stalks" cause a faecal smell. This in turn attracts the small flies and gnats that are to be trapped within the inflorescence. As the time required for successful pollination to occur can be several days, many of the small insects nevertheless die within the flower due to their short lifespan. Therefore, dead insects are frequently found within the inflorescence, when opened, sometimes leading the finder to believe it is a carnivorous plant – but that is not the case. No digestive enzymes or similar components are present; and in fact, once pollinated, the entire inflorescence starts withering except the central part, from which the berries later emerge.[ pp. 35-40]
Pollination-wise, the species of Arum can be split into two (or three) distinct groups. The "cryptic" species have the inflorescence on a relatively short stalk, and the odour released during the thermogenesis is recognizable to the human nose as distinctively faecal. These species are visited by insects with some relation to dung, such as owl-midges (Psychodidae
Psychodidae, called drain flies, sink flies, filter flies, sewer flies, or sewer gnats, is a family of true flies. Some genera have short, hairy bodies and wings giving them a "furry" moth-like appearance, hence one of their common names, moth f ...
) or fungus-gnats ( Sciara). In northern Europe, only the cryptic-flowered species are found.
The other main group are called "flag" species, due to the inflorescence being on a long stalk. These species also exhibit thermogenesis, but if an odour is released it is not recognizable to the human nose, and it is debated if pollinators are attracted by a non-recognizable smell, the thermogenesis itself or visual attraction.
Finally the closely related ''A. idaeum'' and ''A. creticum'' does not seem to fit any of the two groups. ''A. creticum'' appears to be of the "flag" group but, as the only species, emits a pleasing lemony smell. The apparently "cryptic" ''A. idaeum'' does not emit a recognizable smell.[
]
Species
Formerly placed here:
* ''Arisaema triphyllum
''Arisaema triphyllum'', the jack-in-the-pulpit, bog onion, brown dragon or Indian turnip, is a herbaceous perennial plant growing from a corm. It is a highly variable species typically growing in height with three-part leaves and flowers cont ...
'' (syn. ''Arum triphyllum'')
* ''Dracunculus vulgaris
''Dracunculus vulgaris'' is a species of aroid flowering plant in the genus '' Dracunculus'' and the arum family Araceae. Common names include the common dracunculus, dragon lily, dragon arum, black arum and vampire lily. In Greece, part of its n ...
'' (syn. ''Arum dracunculus'')
* '''' (syn. ''Arum cornutum'')
See also
* List of plants known as lily Lily usually refers to herbaceous plants of the genus ''Lilium'', with large showy trumpet-shaped flowers. Many species are cultivated as ornamentals.
Many other plants not closely related to lilies are called lilies, usually because their flowers ...
References
{{Taxonbar, from=Q161121
Araceae genera
Flora of Kurdistan
Taxa named by Carl Linnaeus