Wallflower
Encyclopedia
Erysimum is a genus
that includes about 180 species
, both popular garden plants and many wild forms. The genus Cheiranthus
is sometimes included herein whole or in part. Erysimum has recently adscribed to a monogeneric cruciferous tribe, Erysimeae. This tribe is characterized by sessile, stellate and/or malpighiaceous trichomes, yellow to orange flowers and multiseeded siliques.
, short-lived perennial
herb
s or sub-shrubs, reaching 10-130 cm tall. Most species have stems erect, somewhat winged, canescent with an indumentum of 2-fid hairs, usually 25 ± 53 cm x 2-3 mm in size, and t-shaped trichome
s. Leaves narrow and sessile. Lower leaves linear to oblanceolate pinnatifid with backwardly directed lobes, acute, 50-80 mm x 0.5-3 mm. Stem leaves linear, entire; all canescent with 2-fid hairs; 21-43 mm x 1.5-2 mm. Inflorescence
in raceme, with bright yellow to red or pink bilateral and hermaphodite, hypogynous and ebracteate flower
s. Flowering occurs during spring and summer. One species, Erysimum semperflorens, native to Morocco
and Algeria
, has white flowers. Floral pedicel
ranges between 4 and 7 mm. Four free sepal
s somewhat saccate, light green, 5-7 mm x 1.5-2 mm.
, the Mediterranean region, Europe
, Macaronesia
(Including Cabo Verde), and North America
through Costa Rica
. Many wallflowers are endemic
to small areas, such as the Teide wallflower E. scoparium, endemic to the Teide
volcano on Tenerife
, E. aetnense
endemic to the Etna volcano in Sicily
, the Franciscan wallflower
E. franciscanum, endemic to the northern California
coast, the Sierra Nevada wallflower E. nevadense, endemic to the Sierra Nevada of Spain
, E. moranii from Guadalupe Island
(Mexico), and the endangered Santa Cruz wallflower E. teretifolium, endemic to the inland sandhills of Santa Cruz County, California
. Erysimum kykkoticum
, found only on Cyprus
, is nearly extinct.
s (e.g. Erysimum 'Chelsea Jacket'
) are derived from E. cheiri
(often placed in Cheiranthus), from southern Europe
. Growth is best in dry soils with very good drainage, and they are often grown successfully in loose wall
mortar
, hence the vernacular name. Their flowers are often purple or brown.
e of some Lepidoptera
(butterfly
and moth
) species including the Garden Carpet
(Xanthorhoe fluctuata). In addition, some species of weevils, like Ceutorhynchus chlorophanus, live inside the fruits feeding on the developing seeds. Many species of beetles, bugs and grasshoppers eat on the leaves and stalks. Some mammal
ian herbivores, for example Mule Deer (Odocoileus hemionus) in North America, Red Deer (Cervus elaphus) in Central Europe, or Spanish Ibex (Capra pyrenaica) in the Iberian Peninsula, feed on wallflower flowering and fruiting stalks.
Most wallflowers are pollinator-generalists, their flowers being visited by many different species of bees, bee flies, hoverflies, butterflies, beetles, and ants. However, there some specialist species. For example, Teide wallflower is pollinated almost exclusively by Anthophora
alluadii.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
that includes about 180 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, both popular garden plants and many wild forms. The genus Cheiranthus
Cheiranthus
Cheiranthus , also known as wall-flower, is a large genus from the family Brassicaceae. They are perennial plants grown for their colourful flowers....
is sometimes included herein whole or in part. Erysimum has recently adscribed to a monogeneric cruciferous tribe, Erysimeae. This tribe is characterized by sessile, stellate and/or malpighiaceous trichomes, yellow to orange flowers and multiseeded siliques.
Morphology
Wallflowers are small, annualAnnual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...
, short-lived perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
herb
Herb
Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...
s or sub-shrubs, reaching 10-130 cm tall. Most species have stems erect, somewhat winged, canescent with an indumentum of 2-fid hairs, usually 25 ± 53 cm x 2-3 mm in size, and t-shaped trichome
Trichome
Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...
s. Leaves narrow and sessile. Lower leaves linear to oblanceolate pinnatifid with backwardly directed lobes, acute, 50-80 mm x 0.5-3 mm. Stem leaves linear, entire; all canescent with 2-fid hairs; 21-43 mm x 1.5-2 mm. Inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
in raceme, with bright yellow to red or pink bilateral and hermaphodite, hypogynous and ebracteate flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s. Flowering occurs during spring and summer. One species, Erysimum semperflorens, native to Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
and Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
, has white flowers. Floral pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
ranges between 4 and 7 mm. Four free sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s somewhat saccate, light green, 5-7 mm x 1.5-2 mm.
Distribution
Wallflowers are native to southwest AsiaAsia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, the Mediterranean region, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Macaronesia
Macaronesia
Macaronesia is a modern collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde...
(Including Cabo Verde), and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
through Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
. Many wallflowers are endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to small areas, such as the Teide wallflower E. scoparium, endemic to the Teide
Teide
Mount Teide , is a volcano on Tenerife, Canary Islands. Its summit is the highest point in Spain, the highest point above sea level in the islands of the Atlantic, and it is the third highest volcano in the world measured from its base on the ocean floor, after Mauna Loa and Mauna Kea located in...
volcano on Tenerife
Tenerife
Tenerife is the largest and most populous island of the seven Canary Islands, it is also the most populated island of Spain, with a land area of 2,034.38 km² and 906,854 inhabitants, 43% of the total population of the Canary Islands. About five million tourists visit Tenerife each year, the...
, E. aetnense
Erysimum aetnense
Erysimum aetnense is a short-lived, polycarpic perennial herb endemic and found exclusively on Mt. Etna, in Sicily, Italy.It grows from 1000 to 2000 meters above sea level and inhabits Genista aetnensis shrublands....
endemic to the Etna volcano in Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
, the Franciscan wallflower
Franciscan wallflower
Erysimum franciscanum, commonly known as the Franciscan Wallflower or San Francisco Wallflower, is a plant endemic to the northern California coast, from Sonoma to Santa Cruz Counties. It is a member of the wallflower genus in the mustard family, the Brassicaceae.The plant is a biennial or...
E. franciscanum, endemic to the northern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
coast, the Sierra Nevada wallflower E. nevadense, endemic to the Sierra Nevada of Spain
Sierra Nevada (Spain)
The Sierra Nevada is a mountain range in the region of provinces of Granada and Almería in Spain. It contains the highest point of continental Spain, Mulhacén at 3478 m above sea level....
, E. moranii from Guadalupe Island
Guadalupe Island
Guadalupe Island, or Isla Guadalupe is a volcanic island located 241 kilometers off the west coast of Mexico's Baja California peninsula and some 400 kilometers southwest of the city of Ensenada in Baja California state, in the Pacific Ocean...
(Mexico), and the endangered Santa Cruz wallflower E. teretifolium, endemic to the inland sandhills of Santa Cruz County, California
Santa Cruz County, California
Santa Cruz County is a county located on the Pacific coast of the U.S. state of California, on the California Central Coast. The county forms the northern coast of the Monterey Bay. . As of the 2010 U.S. Census, its population was 262,382. The county seat is Santa Cruz...
. Erysimum kykkoticum
Erysimum kykkoticum
Erysimum kykkoticum is a species of flowering plant in the Brassicaceae family. It is endemic to the Mediterranean island of Cyprus.Its natural habitats are Mediterranean-type shrubby vegetation and rocky areas. It is threatened by habitat loss....
, found only on Cyprus
Cyprus
Cyprus , officially the Republic of Cyprus , is a Eurasian island country, member of the European Union, in the Eastern Mediterranean, east of Greece, south of Turkey, west of Syria and north of Egypt. It is the third largest island in the Mediterranean Sea.The earliest known human activity on the...
, is nearly extinct.
Cultivation
Most wallflower garden cultivarCultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s (e.g. Erysimum 'Chelsea Jacket'
Erysimum 'Chelsea Jacket'
Small and short-lived, Erysimum 'Chelsea Jacket is a perennial cultivar of Erysimum cheiri usually grown for its long-lasting and brightly coloured flowers. It is closely related to Cheiranthus. This plant has been given an RHS Award of Garden Merit...
) are derived from E. cheiri
Erysimum cheiri
Erysimum cheiri is a species of wallflower known by the common name Aegean wallflower in English. It is also known as giroflée and revenelle in French, goldlack in German, alhelí in Spanish and violacciocca in Italian.-Distribution:The plant is native to Europe but it is common and widespread on...
(often placed in Cheiranthus), from southern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. Growth is best in dry soils with very good drainage, and they are often grown successfully in loose wall
Wall
A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air...
mortar
Mortar (masonry)
Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder...
, hence the vernacular name. Their flowers are often purple or brown.
Ecology
Erysimum species are used as food plants by the larvaLarva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of some Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
(butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
and moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
) species including the Garden Carpet
Garden Carpet
The Garden Carpet is a moth of the family Geometridae. It is an abundant and familiar species across its huge range which covers the whole Palearctic region, the Near East and North Africa....
(Xanthorhoe fluctuata). In addition, some species of weevils, like Ceutorhynchus chlorophanus, live inside the fruits feeding on the developing seeds. Many species of beetles, bugs and grasshoppers eat on the leaves and stalks. Some mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian herbivores, for example Mule Deer (Odocoileus hemionus) in North America, Red Deer (Cervus elaphus) in Central Europe, or Spanish Ibex (Capra pyrenaica) in the Iberian Peninsula, feed on wallflower flowering and fruiting stalks.
Most wallflowers are pollinator-generalists, their flowers being visited by many different species of bees, bee flies, hoverflies, butterflies, beetles, and ants. However, there some specialist species. For example, Teide wallflower is pollinated almost exclusively by Anthophora
Anthophora
The bee genus Anthophora is one of the largest in the family Apidae, with over 450 species worldwide in 14 different subgenera. They are most abundant and diverse in the Holarctic and African biogeographic regions. All species are solitary, though many nest in large aggregations...
alluadii.