Tuesday, January 4, 2011

Asplenium anceps, the ancestral patriarch

Many millions of years ago, when Western Europe, North Africa and the Macaronesian Islands were a subtropical paradise with vast forests of laurel, the Asplenium anceps, which over time would be the diploid progenitor of vigorous hybrids, peopled all this vast region in the company of other fern family Aspleniaceae, another ancestor of the trichomanes saga, the diploid Asplenium trichomanes ssp. trichomanes.

Unfortunately the earthly paradises are transient, do not stay forever and just have been replaced by colder climates or warmer, wetter or drier, which subject creatures that inhabit them to severe tests of adaptation. Are then produced mass extinctions, mutations more or less fortunate, strange and seemingly impossible interspecific hybrids and ultimately survive the strongest, the fittest, mutants and hybrids with a genetic combination most appropriate to support the new climate.

The same was what happened to Asplenium anceps. When the climate cooled by successive glaciations, went extinct from north to south and from east to west, being confined to the residual forests of laurel islands of Macaronesia: Canary Islands, Madeira and the Azores, with a temperate climate wet similar to that enjoyed at the time of its greatest expansion.

Asplenium anceps vigorous specimen growing on a soft bed of moss and lichens in a pine forest of  Monte Poiso in Madeira Island at 1500 meters. (Double click on the photo to enlarge)

Asplenium anceps several copies of different ages accompanied by Sibthorpia peregrina, endemic to Madeira, in the same forest as the previous picture, which brings the ideal circumstances for its growth: constant humidity throughout the year, warm temperatures with little variation and shadow permanent.

Since starting its total population decline of Asplenium anceps has gradually decreased, especially in the Canary Islands, where small populations are accompanied by some copies of his vigorous hybrid Asplenium trichomanes ssp. maderense, the result of hybridization between Asplenium anceps and Asplenium trichomanes ssp. quadrivalens. In Tenerife, La Gomera and El Hierro is know a single population in each island with few specimens, being more abundant in the northern half of La Palma.

In the archipelago of the Azores the number of copies is somewhat higher, but is shrinking, becoming more scarce and difficult to locate. Currently only lives in the islands of Faial and Pico, accompanied by another of their hybrid offspring, the Asplenium azoricum, allotetraploid endemic to the Azores, the result of ancient hybridization between Asplenium anceps and other fern genus Asplenium.

Magnificent specimen of the hybrid Asplenium azoricum, photographed on Monte Carneiro on the Island of Faial in the Azores Archipelago. Is very striking resemblance to his father's gross.
In Madeira Island Asplenium anceps populations are more numerous and stable and not currently at risk. As in the Canaries, Madeira shares its habitat with hexaploid hybrid Asplenium trichomanes ssp. maderense.
The fronds of Asplenium anceps are between 5 and 30 centimeters in length. The leaflets are leathery, shiny and plastic, a characteristic they have inherited all their hybrid offspring, both his sons,  Asplenium  azoricum and Asplenium trichomanes ssp. maderense, as his grandson, Asplenium azomanes and his great-grandchildren, Asplenium x tubalense and Asplenium trichomanes nothosubsp. malacitense.

Asplenium anceps frond with pinnae oblong, bright and very leathery to the touch look like plastic.

Surface of a frond of Asplenium anceps.

Underside of the same frond above. The petiole and rachis have a nice brown earth.

When Asplenium anceps grows in a brightly lit place their pinnae adopt a disposition in different levels as a roof. This feature can also be seen in their descendants, especially in his grandson, Asplenium azomanes.

Another characteristic shared by all its descendants is a small auricula at the base of medium and lower leaflets directed toward the apex of the lamina with one, two or three sori on their back. (Double click on the picture to enlarge)

All of the great trichomanes family ferns have two parallel wings of the rachis beam running through it along its length by drawing a canal, which seems to have the function of collecting by capillary and carry moisture from morning dew and horizontal rain collected by the pinnae at the base of the fronds which are the roots.

In this picture you can see two parallel wings on the upper saddle, that run through its entire length.

Wing view in microscope. It is a very thin, transparent film like a cork formed by dry and empty shells of dead cells.
Surface and underside of a frond, which are the two wings of the spine above and below a third wing on the back of the spine, much larger, almost exclusive trait of Asplenium anceps only shared with their offspring Asplenium trichomanes ssp. maderense. All other members of the complex trichomanes have only the two upper wings.

This photo shows well the bottom wing of the rachis, the auricula of the pinnae and  the sori that are arranged in two rows along the midrib of each pinna, except those within the auricula.

Beautiful sporangium of Asplenium anceps after spore dispersal.

And finally, small spores, characteristic of diploid ferns.

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