Friday, June 1, 2012

Crepis triasii, a small rupicolous

The small composite Crepis triasii is endemic of Mallorca, Menorca and Cabrera. Its preferred habitat are the crevices of calcareous rocks north facing. Very rarely grows on level ground, always in vertical walls. Spatulate leaves are arranged in a basal rosette.

Crepis triasii late May growing in a crack of a limestone located in the path leading to the Puig de Ses Tres Creus in the municipality of Soller.

Crepis triasii typical rosette which acts as a parabolic antenna directed towards the light

Two Crepis triasii in April growing together in the same crack.

 Crepis triasii leaves are covered with a thin pilosity more abundant in its lower face. The veins paint a very striking relief grid that facilitates the identification of the plant when no flowers yet.

 Detail of hairs or trichomes. It is appreciated the most abundance in the back of the leaves.

Crepis triasii in a completely vertical rock. Its north facing provides a cool and shaded. In the cocoon of the left we can see very good the small bracts directed outwardly surrounding the flower involucre chapter. This detail is also very useful for identification.

Crepis triasii side view. While the leaves are applied to the rock surface to avoid direct sunlight and sun-loving flowers are arranged on long stems that stretch toward the light with the intention of making the sun shine. They know that pollinating insects with ultraviolet vision will only whether their petals if they are illuminated.

The number of flowers per plant varies greatly, from two or three to more than a dozen. The golden yellow petals colorful gray surfaces of the calcareous rocks.

Flower and flower bud viewed from the side with the details of the bracts at the base of the involucre.

Crepis triasii flowers in late May.

The flowers of the Compositae great family really are inflorescences made up of numerous individual flowers growing together. Usually they have tubulate flowers without petals in the center of the inflorescence and ligulate flowers with large petals on the outside (a typical example is the large sunflower inflorescence). In the case of Crepis triasii all the flowers of the inflorescence are ligulate, all have a large yellow petal with toothed edge, five stamens welded by the anthers, one pistil with the stigma forked and one inferior ovary.

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