Helianthemum nummularium

Helianthemum nummularium
Helianthemum nummularium subsp. glabrum
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Malvales
Family:	Cistaceae
Genus:	Helianthemum
Species:	H. nummularium
Binomial name
Helianthemum nummularium (L.) Mill.

Helianthemum nummularium (Common Rockrose) is a species of rockrose (Cistaceae), native to most of Europe.

Description

It is an evergreen trailing plant with loose terminal clusters of bright yellow, saucer-shaped flowers. In the flower centre is a tight cluster of orange stamens, which are sensitive to the touch, and spread outwards to reveal the tall stigma in the middle. The plant is common on chalk downs, and occasional in other grasslands, always on dry, base-rich soil. Natural rockroses are yellow, but garden varieties range from white through yellow to deep red.

Though the individual blooms are short-lived, the plant produces a mass of flowers through the summer. It needs a dry, sunny place, like a south-facing rockery or meadow. As the Latin name Helianthemum suggests, these are sun-flowers. This is a good nectar source for bees and there are several species of small beetle that feed on the foliage. Common rock-rose is also the food plant for the larvae of several species of moth and butterfly.

It flowers from May until July.

Subspecies

There are eight subspecies:

• Helianthemum nummularium subsp. nummularium. Widespread.
• Helianthemum nummularium subsp. berterianum. Italy, southeast France.
• Helianthemum nummularium subsp. glabrum. Central and southern Europe.
• Helianthemum nummularium subsp. grandiflorum. Central and southern Europe.
• Helianthemum nummularium subsp. obscurum. Eastern Europe.
• Helianthemum nummularium subsp. pyrenaicum. Pyrenees.
• Helianthemum nummularium subsp. semiglabrum. Italy, southeast France.
• Helianthemum nummularium subsp. tomentosum. Southern Europe.

Images

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subsp. grandiflorum (Scop.) Schinz & Thell.

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subsp. nummularium

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subsp. obscurum (Čelak.) Holub)

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  H. nummularium subsp. obscurum
  Germany - Schwäbisch Fränkische Waldberge

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  H. nummularium subsp. obscurum
  Germany - Schwäbisch Fränkische Waldberge

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  H. nummularium subsp. obscurum
  Germany - Schwäbische Alb

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  H. nummularium subsp. obscurum
  Germany - Schwäbische Alb

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Pink-flowered cultivars

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Illustrations

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  flower diagram

Unclassified images of Helianthemum nummularium

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References

• Flora Europaea: Helianthemum nummularium