Monday, December 27, 2010

Asplenium hemionitis, the design done art

Asplenium hemionitis is for me one of the most beautiful ferns Macaronesia. The design of its fronds and the symmetry of its sori are the result of millions of years of evolution. Belongs to the large family of Aspleniaceae and chromosome is diploid (2n = 72). Its fronds, leathery texture and a bright green color, they blend with the ivy leaves, hence the Portuguese called "Feto de folha de hera." In the Canary Islands called "Hierba candil". Need permanent humidity throughout the year, achieved thanks to the phenomenon of horizontal rain water supplies laurel forests, which are their habitat.

Old copy of Asplenium hemionitis on the island of Faial in the Azores Archipelago. On these islands, the humidity is so great that this fern can live in full sun, coming to colonize the walls lining the roads.

Fronds of Asplenium hemionitis, a vivid bright green and leathery texture, and plastic. Are up to 35 cms. with the petiole slightly longer than the blade.

Came to settle in much of Europe and North Africa, coinciding with a period of subtropical climate, warm and moist laurel forests which had its greatest expansion. With the last ice was retreating towards the south and east, fleeing the cold, being held since then in the four archipelagos of Macaronesia, several localities in Portugal where persistent pockets of laurel forest, such as Sierra de Mafra and Sierra de Sintra-Cascais, and some cool, damp locations in northern Africa (Morocco, Algeria and Tunisia).

The symmetry of sori seems designed by a mathematician. The one half is the mirror image of the other half. Have a linear structure and are distributed along the veins of the frond. The photo is immature, yet covered by the indusium which is membranaceous, rigid, narrow and wide.

Underside of frond with sori other mature, with the indusium up for the sporangia to disperse the spores. In the photograph you can see a dark dust around the sori which are the spores. You can also see the long black petiole of fronds. (Double click on the photo to enlarge.)

Detail of mature sori with raised white indusium. Black sporangia are made spores that are dispersed as small catapults.

Sporangium of Asplenium hemionitis, who for some reason could not disperse the spores. Still remain within the transparent bag medium tear, which serves as a womb to maturity.

Asplenium hemionitis tiny spores. The small size indicates its diploid chromosome.

In the town of Taganana on the island of Tenerife was found a beautiful hybrid between Asplenium  onopteris and Asplenium hemionitis called Asplenium x tagananaense.

Asplenium x tagananaense looks antediluvian. The long black stalks its fronds are a feature shared by both parents. The blade has an intermediate structure, although its more reminiscent of the parent sori Asplenium hemionitis. These last two photos belong to the great web of photographs of ferns Andrew Leonard. You can see more photos at this link: Andrew Leonard´s fern site  

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