''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,''Helianthemum''.
Integrated Taxonomic Information System (ITIS). 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 about 110''Helianthemum''.
Flora of China. species 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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Cistaceae The Cistaceae are a small family of plants (rock-rose or rock rose family) known for their beautiful shrubs, which are profusely covered by flowers at the time of blossom. This family consists of about 170(-200) species in nine genera that are ...

. They are widely distributed throughout the Northern Hemisphere, especially in the Mediterranean.

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. 3 ...

species formerly classified as ''Helianthemum'' have been transferred to genus '' Crocanthemum''.

Description

These are usually

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s or subshrubs, and some are

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 ...

annuals or perennials. The

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 ...

are oppositely arranged, but some plants may have alternately arranged leaves along the upper stems. The flowers are solitary or borne in an array of

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 ...

types, such as

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s, or headlike clusters. The flower has three inner

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s and two smaller outer sepals. It has five petals usually in shades of yellow, orange, or pink. The style at the center is tipped with a large stigma. The fruit is a capsule containing many seeds.

Ecology

''Helianthemum'' are known to form

symbioses Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

with

mycorrhiza A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant ...

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

. In the Mediterranean they are associated with Terfeziaceae, the desert truffles. Together, plant and fungus may have a beneficial effect on the arid local landscapes, preventing

soil erosion Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and ...

and

desertification Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused by ...

. Some symbiotic pairs include ''Helianthemum salicifolium'' and the truffle ''Tirmania nivea'', and ''H. guttatum'' and ''T. pinoyi''. One of the most commonly observed mycorrhizae on ''Helianthemum'' is a member of a different family, '' Cenococcum geophilum''. This fungus is not host-specific, and it often associates with

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

s, as well. Some studies suggest that ''Helianthemum'' and oaks growing together in a habitat may "share" their mycorrhizae. ''Helianthemum'' are food plants for the

larva A larva (; plural larvae ) 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. The ...

e of some

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

species, such as the large grizzled skipper and the

silver-studded blue The silver-studded blue (''Plebejus argus'') is a butterfly in the family Lycaenidae. It has bright blue wings rimmed in black with white edges and silver spots on its hindwings, lending it the name of the silver-studded blue. ''P. argus'' can be ...

. The

leaf miners A leaf miner is any one of numerous species of insects in which the larval stage lives in, and eats, the leaf tissue of plants. The vast majority of leaf-mining insects are moths (Lepidoptera), sawflies (Symphyta, the mother clade of wasps), ...

'' Bucculatrix helianthemi'' and '' B. regaella'' both feed exclusively on ''Helianthemum sessiliflorum'', as does '' Coleophora eupreta''. '' C. ochrea'' is limited to ''Helianthemum'', and '' C. bilineella'' and '' C. potentillae'' have been observed on the genus.

Cultivation

Several ''Helianthemum'' species, and the numerous

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

s and

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s derived from them, are widely grown as

ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...

s, popular in

rockeries A rock garden, also known as a rockery and formerly as a rockwork, is a garden, or more often a part of a garden, with a landscaping framework of Rock (geology), rocks, stones, and gravel, with planting appropriate to this setting. Usually t ...

. A broader range of colours is available among the cultivars, including bright salmon-pink to dark red. They are best grown in well-drained soil in full sun, and have a long flowering period from spring to summer. Numerous cultivars have gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

: *'Amy Baring' (yellow) *'Fire Dragon' *'Henfield Brilliant' (scarlet) *'Jubilee' (pale yellow) *'Mrs C.W. Earle' (red) *'Rhodanthe Carneum' (pink) *'The Bride' (white) *'

Wisley __NOTOC__ Wisley is a village and civil parish in Surrey, England between Cobham and Woking, in the Borough of Guildford. It is the home of the Royal Horticultural Society's Wisley Garden. The River Wey runs through the village and Ockham and ...

Primrose' (primrose yellow)

Selected species

Species include: *'' Helianthemum aegyptiacum'' *'' Helianthemum almeriense'' *'' Helianthemum apenninum'' – white rockrose *'' Helianthemum asperum'' *'' Helianthemum canariense'' *''

Helianthemum canum ''Helianthemum oelandicum'', commonly called hoary rockrose, is a low growing plant confined to rocky dry calcareous areas especially close to the sea. Description The plant typically has a central stock from which numerous branches radiate hor ...

'' – hoary rockrose *''

Helianthemum caput-felis ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum cinereum'' *'' Helianthemum coulteri'' see: Crocanthemum coulteri *'' Helianthemum croceum'' *'' Helianthemum guerrae'' *''

Helianthemum hirtum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum hymettium'' *'' Helianthemum jonium'' *''

Helianthemum kahiricum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum lavandulifolium'' *'' Helianthemum ledifolium'' *''

Helianthemum leptophyllum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum lipii'' *'' Helianthemum lunulatum'' *'' Helianthemum marifolium'' *'' Helianthemum morisianum'' *'' Helianthemum nummularium'' – common rockrose *'' Helianthemum oelandicum'' – alpine rockrose (

syn. The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

''Helianthemum montanum'') **''Helianthemum oelandicum'' subsp. ''alpestre'' (syn. ''H. alpestre'') **''Helianthemum oelandicum'' subsp. ''italicum'' (syn. ''H. italicum'') **''Helianthemum oelandicum'' subsp. ''oelandicum'' **''Helianthemum oelandicum'' subsp. ''orientale'' (syn. ''H. orientale'') **''Helianthemum oelandicum'' subsp. ''rupifragum'' (syn. ''H. rupifragum'') *'' Helianthemum origanifolium'' *''

Helianthemum pannosum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum papillare'' *'' Helianthemum piliferum'' *'' Helianthemum pilosum'' *''

Helianthemum rossmaessler ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum salicifolium'' *'' Helianthemum sanguineum'' *''

Helianthemum sessiliflorum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *'' Helianthemum songaricum'' *''

Helianthemum squamatum ''Helianthemum squamatum'' is a species of low woody herbaceous plant native to Spain and Algeria. It is the only known species able to extract water of crystallization from rock and is able to derive up to 90% of its fluid requirements from gyps ...

'' *'' Helianthemum stipulatum'' *'' Helianthemum villosum'' *''

Helianthemum virgatum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *''

Helianthemum viscarium ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

'' *''

Helianthemum viscidulum ''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...

References

External links

Flora Europaea: ''Helianthemum''eFloras search results for ''Helianthemum''
{{Taxonbar, from=Q162895 Malvales genera Taxa named by Philip Miller