Centaurea Cineraria

''Centaurea cineraria'', the velvet centaurea, is also known as dusty miller and silver dust (though these latter two names may also apply to ''Jacobaea maritima'' and ''Silene coronaria''). ''Centaurea cineraria'' is in the family Asteraceae and is endemic to Italy. In natural settings, it grows on coastal cliffs, ranging from 0–350 m above sea level. Mature plants may reach in height. ''Centaurea cineraria'' produces purple flowers.

''Centaurea cineraria'' is taxonomically complicated, with several described subspecies and lots of geographic variation. Members of the ''C. cineraria'' group have variously been treated as full species, as subspecies, or simply as regional variations.

In Horticulture

''Centaurea cineraria'' is commonly cultivated for its foliage. Depending on climate, it can be grown as either an annual or as a perennial. In cultivation, this species prefers full sun and well-drained soil.

''Centaurea cineraria'' is sometimes referred to as ''Centaurea gymnocarpa'' within the horticultural trade, due to both taxonomic confusion and/or potential hybridization between ''C. cineraria'' and ''C. gymnocarpa'' in cultivation. However, cultivated material seems to mostly consist of ''C. cineraria'' in a narrower sense, with some possible introgression from other members of the ''C. cineraria'' group (including ''C. gymnocarpa''). True ''C. gymnocarpa'' is a rare plant in the wild and likely does not exist in cultivation outside of conservation settings. Despite past work that sometimes treated ''C. gymnocarpa'' as conspecific with ''C. cineraria'', current work supports both taxa at the species level.

''Centaurea cineraria'' occasionally escapes from cultivation, but, at least in North America, this has not resulted in established exotic populations. This species is, however, naturalized in New Zealand.

In the UK ''Centaurea cineraria'' subsp. ''cineraria'' has gained the Royal Horticultural Society's Award of Garden Merit.

Because of similar leaf shape, leaf hairiness, and leaf color, there has been much confusion in the horticultural world between ''C. cineraria'' and the unrelated ''Jacobaea maritima'' (with ''Senecio cineraria'' being an old name for ''Jacobaea maritima''). ''Jacobaea maritima'' has similar foliage to ''C. cineraria'' (indeed, "cineraria" means "ash-gray colored"). Cultivars like ‘Silver Dust’, ‘Silver Lace’, and ‘Cirrus’ are sometimes mistakenly referred to as ''C. cineraria'' but these cultivars actually pertain to ''J. maritima''. The cultivar 'Colchester White' (named for the leaf color, not the flower color) does actually pertain to ''C. cineraria'' and is the most common cultivar of this species. This confusion has also resulted in many images on the internet being mistakenly identified, resulting in identification of cultivated material challenging, especially without reproductive parts.

References

* Cela Renzoni G, Viegi L.. 1983. Centaurea cineraria s.l. (Asteraceae) in Italia: revisione citotassonomica.. Atti della Società Toscana di Scienze Naturali. Memorie serie B, 89: pp. 99–144. Società Toscana di Scienze Naturali, Pisa.
* Ellis, Barbara W., "Taylor's Guide to Annuals, How to Select and Grow More Than 400 Annuals, Biennials, and Tender Perennials", 1999 Haughton Mifflin Company, New York, NY
* Armitage, Allan M., "Armitage's Manual of Annuals, Biennials, and Half-Hardy Perennials", illustrated Asha Kays and Chris Johnson, 2001 Timber Press Inc., Singapore

External links

United States Department of Agriculture
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{{Taxonbar, from=Q4117857

cineraria
Plants described in 1753
Taxa named by Carl Linnaeus