Helianthemum

taxobox
name = "Helianthemum"

"Helianthemum" (rockrose, sunroses, rushrose, or helianthemum) is a genus of about 110 species of evergreen or semi-evergreen subshrubs. They are widely distributed in the Americas, Europe, and from North Africa to Asia Minor and Central Asia, with the centre of diversity in the Mediterranean region.

The leaves are opposite, simple oval, 1-4 cm long and 0.5-2 cm broad, varying from glossy green to tomentose grey-green. The flowers are 2-4 cm diameter, with five petals, white or yellow, occasionally tinged pink; in some species the flowers are bicoloured with a brighter yellow centre to act as a 'target' for pollinating insects.

"Helianthemum" species are used as food plants by the larvae of some Lepidoptera species including Large Grizzled Skipper and the bucculatricid leaf-miners "Bucculatrix helianthemi" and "Bucculatrix regaella" (which both feed exclusively on "Helianthemum sessiliflorum") and the "Coleophora" case-bearers "C. bilineella", "C. eupreta" (feeds exclusively on "H. sessiliflorum"), "C. ochrea" (feeds exclusively on "Helianthemum") and "C. potentillae".

;Selected species
*"Helianthemum aegyptiacum"
*"Helianthemum almeriense"
*"Helianthemum apenninum" - White Rockrose
*"Helianthemum asperum"
*"Helianthemum bicknellii"
*"Helianthemum canadense" - Frostweed
*"Helianthemum canum" - Hoary Rockrose
*"Helianthemum caput-felis"
*"Helianthemum cinereum"
*"Helianthemum corymbosum"
*"Helianthemum croceum"
*"Helianthemum greenei" - Island Rushrose
*"Helianthemum guerrae"
*"Helianthemum hirsutissimum"
*"Helianthemum hirtum"
*"Helianthemum hymettium"
*"Helianthemum jonium"
*"Helianthemum lavandulifolium"
*"Helianthemum ledifolium"
*"Helianthemum leptophyllum"
*"Helianthemum lunulatum"
*"Helianthemum marifolium"
*"Helianthemum morisianum"
*"Helianthemum nummularium" - Common Rockrose
*"Helianthemum oelandicum" - Alpine Rockrose (syn. "Helianthemum montanum")
**"Helianthemum oelandicum" subsp. "oelandicum"
**"Helianthemum oelandicum" subsp. "alpestre" (syn. "Helianthemum alpestre")
**"Helianthemum oelandicum" subsp. "italicum" (syn. "Helianthemum italicum")
**"Helianthemum oelandicum" subsp. "orientale" (syn. "Helianthemum orientale")
**"Helianthemum oelandicum" subsp. "rupifragum" (syn. "Helianthemum rupifragum")
*"Helianthemum origanifolium"
*"Helianthemum pannosum"
*"Helianthemum papillare"
*"Helianthemum piliferum"
*"Helianthemum pilosum"
*"Helianthemum rossmaessler"
*"Helianthemum salicifolium"
*"Helianthemum sanguineum"
*"Helianthemum scoparium" - Rushrose
*"Helianthemum sessiliflorum"
*"Helianthemum songaricum"
*"Helianthemum spartioides"
*"Helianthemum squamatum"
*"Helianthemum stipulatum"
*"Helianthemum suffrutescens" - Amador Rushrose
*"Helianthemum villosum"
*"Helianthemum virgatum"
*"Helianthemum viscarium"
*"Helianthemum viscidulum"

Cultivation and uses

Several "Helianthemum" species, and the numerous hybrids and cultivars derived from them, are widely grown as ornamental plants, popular in rockeries. A broader range of colours is available among the cultivars, including bright salmon-pink to dark red.

References

* [http://rbg-web2.rbge.org.uk/cgi-bin/nph-readbtree.pl/feout?FAMILY_XREF=&GENUS_XREF=Helianthemum&SPECIES_XREF=&TAXON_NAME_XREF=&RANK=species Flora Europaea: "Helianthemum"]
* [http://www.efloras.org/browse.aspx?flora_id=0&name_str=Helianthemum&btnSearch=Search eFloras search results for "Helianthemum"]

External links

* [http://www.helianthemums.co.uk Helianthemums.co.uk for further information]