Jacobaea maritima
Encyclopedia
Jacobaea maritima is a perennial plant
species in the genus Jacobaea
in the family Asteraceae
, native to the Mediterranean region. It was formerly placed in the genus Senecio
, and is still widely referred to as Senecio cineraria; see the list of synonyms (right) for other names.
It is widely cultivated as an ornamental plant
for its white, felt
-like tomentose
leaves; in horticultural
use, it is also sometimes called "dusty miller
", a name shared with several other plants that also have silvery tomentose leaves; the two most often to share the name are Centaurea cineraria
and Lychnis coronaria
.
-wooly
, heat and drought
tolerant evergreen
subshrub
growing to 0.5–1 m tall. The stems are stiff and woody at the base, densely branched, and covered in long, matted grey-white to white hairs. The leaves
are pinnate or pinnatifid, 5–15 cm long and 3–7 cm broad, stiff, with oblong and obtuse segments, and like the stems, covered with long, thinly to thickly matted with grey-white to white hairs; the lower leaves are petiolate and more deeply lobed, the upper leaves sessile and less lobed. The tomentum is thickest on the underside of the leaves, and can become worn off on the upper side, leaving the top surface glabrous with age. The flower
s are yellow, daisy-like in dense capitula
12–15 mm diameter, with central disc florets surrounded by a ring of 10–13 ray florets, and enclosed in a common whorl of bract
s at the base of the capitulum
. The seed
s are cylindrical achenes.
, northern Algeria
, Tunisia
), southern Europe (Spain
, Gibraltar
, southern France
including Corsica
, Italy
including Sardinia
and Sicily
, Malta
, Slovenia
, Croatia
, Bosnia, Kosovo
, Montenegro
, Serbia
, Republic of Macedonia
, Greece
,), and the far west of Asia (Turkey
). It occurs primarily on cliffs and rocky coastal sites, more rarely inland.
It is also naturalised
further north in Europe (north to Great Britain
and Ireland
, where occurring mainly in mild coastal areas) and locally in North America
.
s (e.g. Anthidium manicatum
and Anthidium oblongatum
in Megachilidae
) for nest-building.
Hybrids are known with Jacobaea erucifolia
and Jacobaea vulgaris; the hybrid with J. vulgaris is fertile, producing a wide range of intermediate progeny.
Jacobaea maritima is widely used in horticulture for its silvery foliage. It is winter hardy in USDA Zones 8-10
, tolerating winter temperatures down to -12° to -15° C, tolerant of light shade but preferring full sun. In colder areas it is grown as an annual plant
. Many cultivar
s have been selected for particularly dense silvery tomentum, such as 'Cirrus', 'New Look', 'Ramparts', 'Silverdust', 'Silver Filigree', and 'White Diamond'. It has been recommended in North America for its fire resistance resistance to browsing by deer
, and its salt tolerance
.
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...
species in the genus Jacobaea
Jacobaea
Jacobaea is a genus of the tribe Senecioneae and the family Asteraceae. Most if not all of its members used to be placed in the genus Senecio.-Species:*Jacobaea abrotanifolia*Jacobaea adonidifolia Loisel.*Jacobaea alpina...
in the family Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
, native to the Mediterranean region. It was formerly placed in the genus Senecio
Senecio
Senecio is a genus of the daisy family that includes ragworts and groundsels. The flower heads are normally rayed, completely yellow, and the heads are borne in branched clusters...
, and is still widely referred to as Senecio cineraria; see the list of synonyms (right) for other names.
It is widely cultivated as an ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
for its white, felt
Felt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
-like tomentose
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 :...
leaves; in horticultural
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
use, it is also sometimes called "dusty miller
Dusty Miller
Joan 'Dusty' Miller, O.Ont is a former Canadian politician who served as the first woman mayor of Thunder Bay, Ontario from 1978 until the end of 1980 when she was defeated. Miller was married to Lakehead University history professor Tom Miller. Prior to her political activity, she was active in...
", a name shared with several other plants that also have silvery tomentose leaves; the two most often to share the name are Centaurea cineraria
Centaurea cineraria
Centaurea cineraria, the Velvet Centaurea, is – like some other plants – also known as "dusty miller". It is a small plant in the family Asteraceae and originates from the Island of Capraia in Italy, where it is called fiordaliso scogliere.The mature plants will grow from 15 cm to...
and Lychnis coronaria
Lychnis coronaria
Silene coronaria is a species of flowering plant in the carnation family, Caryophyllaceae, that is native to Asia and Europe. Common names include Dusty Miller , Mullein-pink, Rose Campion, and Bloody William. It is cultivated as an ornamental.-References:* Armitage, Allan M...
.
Description
Silver Ragwort is a very whiteWhite
White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
-wooly
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 :...
, heat and drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
tolerant evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
subshrub
Subshrub
A subshrub or dwarf shrub is a short woody plant. Prostrate shrub is a similar term.It is distinguished from a shrub by its ground-hugging stems and lower height, with overwintering perennial woody growth typically less than 10–20 cm tall, or by being only weakly woody and/or persisting...
growing to 0.5–1 m tall. The stems are stiff and woody at the base, densely branched, and covered in long, matted grey-white to white hairs. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are pinnate or pinnatifid, 5–15 cm long and 3–7 cm broad, stiff, with oblong and obtuse segments, and like the stems, covered with long, thinly to thickly matted with grey-white to white hairs; the lower leaves are petiolate and more deeply lobed, the upper leaves sessile and less lobed. The tomentum is thickest on the underside of the leaves, and can become worn off on the upper side, leaving the top surface glabrous with age. The 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 are yellow, daisy-like in dense capitula
Capitulum
The term Capitulum can refer to several things:*In botany, a type of flower head where the bracts are located under the basis, such as a daisy's*Also in botany, the top of a Sphagnum moss plant with compact clusters of young branches....
12–15 mm diameter, with central disc florets surrounded by a ring of 10–13 ray florets, and enclosed in a common whorl of bract
Bract
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 often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s at the base of the capitulum
Capitulum
The term Capitulum can refer to several things:*In botany, a type of flower head where the bracts are located under the basis, such as a daisy's*Also in botany, the top of a Sphagnum moss plant with compact clusters of young branches....
. The seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s are cylindrical achenes.
Distribution
Jacobaea maritima is native to the western and central Mediterranean region, in northwest Africa (MoroccoMorocco
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...
, northern 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...
, Tunisia
Tunisia
Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...
), southern Europe (Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, Gibraltar
Gibraltar
Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean. A peninsula with an area of , it has a northern border with Andalusia, Spain. The Rock of Gibraltar is the major landmark of the region...
, southern France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
including Corsica
Corsica
Corsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
including Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...
and 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,...
, Malta
Malta
Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...
, Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...
, Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
, Bosnia, Kosovo
Kosovo
Kosovo is a region in southeastern Europe. Part of the Ottoman Empire for more than five centuries, later the Autonomous Province of Kosovo and Metohija within Serbia...
, Montenegro
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
, Serbia
Serbia
Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...
, Republic of Macedonia
Republic of Macedonia
Macedonia , officially the Republic of Macedonia , is a country located in the central Balkan peninsula in Southeast Europe. It is one of the successor states of the former Yugoslavia, from which it declared independence in 1991...
, Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
,), and the far west of Asia (Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
). It occurs primarily on cliffs and rocky coastal sites, more rarely inland.
It is also naturalised
Naturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
further north in Europe (north to Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
, where occurring mainly in mild coastal areas) and locally in 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...
.
Ecology
As with many other densely tomentose plants, the tomentum on the leaves is used by some species of beeBee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s (e.g. Anthidium manicatum
Anthidium manicatum
Anthidium manicatum, common name European wool carder bee, is a species of bee in the family Megachilidae, the leaf-cutter bees or mason bees....
and Anthidium oblongatum
Anthidium oblongatum
Anthidium oblongatum is a species of bee in the family Megachilidae, the leaf-cutter, carder, or mason bees.-Synonyms:Synonyms for this species include:*Apis manicata_homonym Linnaeus, 1798*Anthophora oblongata Illiger, 1806...
in Megachilidae
Megachilidae
The Megachilidae are a cosmopolitan family of solitary bees whose pollen-carrying structure is restricted to the ventral surface of the abdomen...
) for nest-building.
Hybrids are known with Jacobaea erucifolia
Jacobaea erucifolia
Jacobaea erucifolia or hoary ragwort is a species of the genus Jacobaea and the family Asteraceae....
and Jacobaea vulgaris; the hybrid with J. vulgaris is fertile, producing a wide range of intermediate progeny.
Cultivation and uses
Hardiness zone
A hardiness zone is a geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions, including its ability to withstand the minimum temperatures of the zone...
, tolerating winter temperatures down to -12° to -15° C, tolerant of light shade but preferring full sun. In colder areas it is grown as an annual plant
Annual 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...
. Many cultivar
Cultivar
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 have been selected for particularly dense silvery tomentum, such as 'Cirrus', 'New Look', 'Ramparts', 'Silverdust', 'Silver Filigree', and 'White Diamond'. It has been recommended in North America for its fire resistance resistance to browsing by deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
, and its salt tolerance
Halophyte
A halophyte is a plant that grows where it is affected by salinity in the root area or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. An example of a halophyte is the salt marsh grass Spartina alterniflora . Relatively few plant species are...
.