Sunday, December 26, 2010

Marsilea strigosa. It was believed extinct.

It was an error with no other explanation for not having consulted experts in the Balearic Islands. To have done so had it not included among the plants that are extinct in the Red List of Spanish Vascular Flora of 2008. Fortunately the mistake was quickly remedied by the excellent botanical Balearic University. The Marsilea strigosa, therefore, still very much alive, but living dangerously threatened, exposed, yes, predation of the territory where its habitat.

This fern lives in temporary ponds that form with the first rains of autumn depressions in the limestone. Its life cycle is completed in about seven months. During the remaining five months remain in summer lethargy in the form of rhizomes buried in the dried mud from the bottom of the raft.

Temporary raft filled with water in February, surrounded by Mediterranean scrub: wild olive, mastic, thickets, asphodelus, Aleppo pine, rhamnus, orchids, crocus, asparagus, rosemary, gageas, etc ...

The life cycle thus begins in late September or early October, as soon as wet sludge from the pond, raising the Marsilea the summer lethargy. Internodes of rhizomes sprout long stalked fronds that grow to the surface of the water and, when reached, open the four leaflets in the form of four-leaf clover, which manage to stay afloat through the issue of tiny air bubbles through the stomata on the underside of the pinnae. Meanwhile, the rhizome is accumulating nutrients through the energy from sunlight.

Marsilea strigosa fronds floating and by photosynthesis in the sun with their rhizomes buried in the mud. They share the pond with tadpoles of the toad Bufo balearicus.

In March, the buds of internodes produced sporocarps called fertile fronds with sporangia filled with spores, which remain submerged in the mud at the bottom of the raft. A mid-spring sporangia open and disperse the spores into the water. These can be top female, or male and small megaspores, microspores. Germinate quickly and megaspores are born with a female gametophytes oosphere, which is fertilized by a antherozoids male gametophytes produced by infants of the microspores. The oosphere fertilized embryo emerges with a tiny frond and an outline of rhizome, which in a few weeks should stop growing and go dormant since late spring, the pond dries up and the tiny newborn Marsilea remains buried in the dried mud, waiting to pass the long months of summer arrive Mallorcan following the first rains of autumn.

Same raft before mid-June, completely dry, with dormant rhizomes Marsile by aestivation.

On the surface of dried sludge can be distinguished small marks left by the passage of shorebirds, Mediterranean tortoises (Testudo hermanni) and rabbits, just before it dries completely.

Botanical experts, University Balearic and environmental groups have for years been asking the political power to protect these habitats, so fragile and so vulnerable to human greed. So far no one has heard and this beautiful aquatic fern, this great little botanical treasure continues year after year doing their life cycle, oblivious to the serious danger to his life.

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