why mediterranean in lower case? 
 

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The endangered fiordaliso di Capraia (Centaurea gymnocarpa) in its native cliff habitat.

Photo by Brunello Pierini.


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The plant distributed in the nursery trade around the world as Centaurea gymnocarpa.


Floral comparison


There are a number of very similar Centaurea species along the Italian coastline and distinguishing between them is difficult. One of the ways botanists differntiate these species is by the finge on their involucre bracts:


A flower bud of the true C. gymnocarpa showing bracts with smooth edges and a little tuft of fringe at the tip.

An artist's depiction of the involucre bracts of the true C. gymnocarpa


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A bud of the garden plant grown as C. gymnocarpa with larger fringe extending down the side of the involucre bract, more typical of C. cineraria, a closely related species from Southern Italy.

Centaurea gymnocarpa Moris & De Not. 1839

ken…TAU…r⋅r⋅reh…ah  goom…noh…KAR⋅R⋅R…pah

Asteraceæ Carduoideæ Cardueæ Centaureinæ

Has also been placed in Compositæ

Centaurea : centaureum - name for the centaury • gymnocarpa : Greek: gymnos - naked, unclad; karpos - fruit

Capraian cornflower Italiano: fiordaliso di Capraia


Synonymy: Centaurea cineraria var. gymnocarpa (Moris & De Not.) Fiori 1927


This plants should not be confused with the garden plant grown under the same name, which this author has found to be a hybrid or polyploid mutation.

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Location of Isola Capraia in the Tuscan Archipelago (map by Norman Einstein courtesy of Wikipedia)

The true Centaurea gymnocarpa is a rare, endangered species endemic to a remote island in the Tuscan Archipelago - Isola Capraia (not the better known Isola di Capri, much further south in the Tyrrhenian Sea, near Naples).  Capraia's closest mainland Italian port is Livorno, but the island is in fact much closer to French Corsica.

I am currently growing the true C. gymnocarpa from seed provided by Professor Lucia Viegi of Università di Pisa, Tuscany, Italy, who is one of the authors of a recent revision of the 'Cineraria' group in the genus Centaurea (see citation list below).  It is clearly a different plant and I will report more fully on its characteristics as I observe its flowering.


Why is this important?

Endangered plants need careful protection by informed individuals.  The ubiquity of an apparent garden hybrid under the name of a IUCN Red List plant is directly counter to this aim, leading to misunderstanding and confusion (and possible 'pollution' of the endangered plant's gene pool by inadvertent cross-pollination).

The plant in gardens is certainly a desirable addition to garden and should continue to be grown, but naming it more according to its apparent hybrid status would honor the needs of these isolated populations of the endangered species.

Foliage comparison


The true C. gymnocarpa growing in Orto dei Semplici Elbano, Isola d'Elba. (photo by Daniel Mount)

 

The plant grown in gardens — this one in Berkeley, California — as C. gymnocarpa or C. cineraria. (photo by Seán O'Hara)


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Comparison of the true C. gymnocarpa (left) and true C. cineraria (right) with the plant grown in gardens (center) variously under each name.

Most people find it hard to distinguish between the leaf forms of these closely related plants.  Since these species tend to have different young vs. mature leaves - basal leaves roughly pinnate becoming bipinnate in more mature leaves - this adds to the confusion.  But a little close attention does show that C. gymnocarpa's leaf divisions tend to remain more pinnatifid whereas the other two tend to become more fully pinnatisect.  Also, photos of C. gymnocarpa regularly show a tendency towards being interruptedly pinnate unlike the others.  The garden plant's leaves are much larger and graceful (surely the reason why it found its way into horticulture), even when the plants are grown under similar conditions.  Interestingly, C. gymnocarpa leaves take on a purplish tint as they dry whereas those of C. cineraria do not.  One of the main ways to tell the species appart is the amount and location of fringe-like hairs on the corolla bracts (see left sidebar) which require a magnifying lens to see clearly.

Seán O'Hara




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From The IUCN Red List of Threatened Species:

Centaurea gymnocarpa is endemic to the island of Capraia, a small island which is part of the Tuscan Archipelago, Italy.

The population size is estimated to be less than 250 individuals.  The decline in this small population is not yet significant enough to classify this species as Critically Endangered, as only one subpopulation, of 20 individuals, is under threat.

It is a herbaceous species that colonizes cracks and fissures of rock faces, growing on acid rocks.  It is found in association with Linaria capraia and other endemic species such as Silene badaroi and Galium caprarium.

C. gymnocarpa belongs to the group known as the "cineraria" group.  This group probably was once a single species when the land masses were united, but as islands were formed, new species evolved on each island.  This means that today there are a number of closely related species of Centaurea in the Mediterranean growing on rocky seaward cliffs, all probably related to a common ancestor.

The subpopulation, situated between Paese and Porto, is severely threatened by competition from two foreign invaders: Carpobrotus acinaciformis and Senecio angulatus.  In recent years, these two invasive species have been expanding in Capraia, but do not yet grow in the areas where C. gymnocarpa occurs, which are, for the most part, far away from areas of human habitation.

This species is protected by the law 56/2000, which is a law guiding biodiversity conservation in the Tuscan region, and is quite similar to the EC Habitats Directive.  Under this law, it is forbidden to collect any species in this genus.

Four of the eight known subpopulations occur in the Tuscan Archipelago National Park.  The Park includes a protected terrestrial area of just under 18,000 ha, and a marine protected area of approximately 60,000 ha (making it the largest European marine park).  The objective of the Tuscan Archipelago National Park is to protect this fragile natural environment, which is very rich in cultural and scientific values.

Monitoring of all subpopulations is needed, and a programme to remove invasive alien plants which threaten one of the subpopulations needs to be undertaken.  Efforts to ensure that these alien species do not start growing in the other areas where this species is found are also very important.  Once the alien species have been eradicated, a re-introduction programme will be planned, using specimens propagated from the threatened population.


References


William T Stearn. 2004. Botanical Latin. Timber Press. ISBN 0881926272 / ISBN13 9780881926279 http://gimcw.org/books/bookinfo.cfm?bookid=blwts

Germplasm Resources Information Network (GRIN). National Plant Germplasm System. USDA Agricultural Research Service. Website http://www.ars-grin.gov/npgs/aboutgrin.html

International Union for Conservation of Nature and Natural Resources. The IUCN Red List of Threatened Species. Website http://www.iucnredlist.org/apps/redlist/details/61620/0 [accessed 1 June 2011].

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. Centaurea_cineraria_in_Italia.pdf