Sunday, February 12, 2012

Sibthorpia africana: a Balearic endemism

Sibthorpia africana is a very inconspicuous little plant, insignificant, humble, shy, very fuzzy, who like to live rooted on the moss and lichens that filled the cool, moist rock crevices oriented north. Hates direct sun and to avoid it, as if its shyness prevented it from lean, when its panel-growth stems reach the edge of the cleft stick to the limestone rocks and moss, assuming the appearance of a green carpet. Thus only the rays of biased sunrise and sunset, or the northeast and southwest, staying in the shade during the hottest hours of the day. 

Sibthorpia africana flowering stalk of early May the moss growing on a rocky crevice that fills the Serra de Tramuntana in Mallorca at 110 meters. The stems can reach 40 centimeters in length.

Sibthorpia africana late October in its preferred habitat, the crack of a rock facing north.

In this image Sibthorpia africana heliofobia is so obvious that no leaf dares to stand outside the crack.  

The botanist who named it suffered a slip and called African, but not be, because in reality it is a strictly Balearic endemism living in all the islands except in Formentera. Interestingly the only plant of this genus living in Africa is Sibthorpia europaea.

First flower of Sibthorpia africana in late April. The flowers of this Scrophulariaceae are usually solitary. Exceptionally we can find two flowers on the same stem.

The genus Sibthorpia has only five species worldwide, distributed in temperate and subtropical regions of Europe, Africa and America. They are perennials and creeping stems which tend to root where its nodes touch the ground, thus facilitating their survival and expansion into adjacent cracks.

Another flower in early May. The Sibthorpia africana live from sea level to 1300 meters. It blooms in April, May and June.

 Most flowers of Sibthorpia africana are pentamerous with five petals of a lively lemon yellow, rarely white, five stamens and a pistil. Exceptionally, they can submit up to eight petals.

Lateral view of a flower which shows the abundant hairiness of the calyx and underside of leaves. The hairs can be no excretory the longest and glandular with a tiny gland at the end the shorter. In no case exceed two millimeters in length.

The leaves are kidney-shaped with serrated edge and very hairy, especially on the underside. Each leaf has between 5 and 14 teeth broad, acute to obtuse and densely hairy petiole longer than the limb.

As the moss which grows on, Sibthorpia africana survives the long, hot and dry Balearic summer months entering in aestivation, with most of dried leaves, waiting patiently the first rains of autumn.

No comments:

Post a Comment