Sempervivum tectorum

Roof House Leek (Sempervivum tectorum ), Swabian Alb, Germany.

The Roof House Leek (Sempervivum tectorum ), also True Houseleek, Common Houseleek, thunder root, called Alpine Houseleek, a plant belonging to the family of the Crassulaceae ( Crassulaceae ) and the genus Houseleeks (Sempervivum ) is heard.

Description

Sempervivum tectorum grows with open rosettes 5-7 (rarely 2 to 20 ) inches in diameter, 4 to 10 centimeters long builds strong runners. The oblong lanceolate to obovate leaves are usually dark green to Glauk and both sides convex. The color is, however, highly variable and also shows yellow, brown and red. The leaf blade is 20 to 60 millimeters long and 10 to 15 millimeters wide and has a fitted top. The eyelashes are conspicuously white, but do not have glandular heads. The Sempervivum tectorum var tectorum variety, the leaf surfaces glabrous or with only a very few scattered hairs occupied. The Sempervivum tectorum var arvernense variety, however, has short glandular - downy -haired leaf areas.

The flowering stems reach a length of 20 to 60 centimeters, with indigenous representatives in the mountains it is hardly more than 35 cm high. The large, dense flower formation is more or less flat or rispenähnlich. It consists of 40 to over 100 individual flowers. The flowers are usually ten to dreizehnzählig, but can vary between a number of six to 16 petals. Their pointed sepals are about 8 mm long and grow together in about 4 millimeters. The whitish, cloudy pink or purple, pointed petals are linear to lanceolate and 9 to 12 millimeters long and about 2 mm wide. At their base they are ciliate and pubescent. The stamens are bright rotpurpurfarben, the stamens red. The pfriemliche pen is purple something. The green Nektarschüppchen are semicircular.

The number of chromosomes is rare or.

Systematics and distribution

The distribution area of Sempervivum tectorum includes the mountains of Western, Central and Southern Europe, extending from the central Pyrenees in the Massif Central to the southeastern Alps and the southern Apennines. The species is often cultivated. It is therefore neglected from Scandinavia to Ireland, the rest of Europe and the Caucasus, Iran.

The first description was in 1753 by Linnaeus in Species Plantarum. A synonym is Sedum tectorum. We distinguish the following varieties:

• Sempervivum tectorum var arvernense This variety has not only ciliated on the edge, but also fluffy hairy leaf surfaces, but these are short glandular hairy. It occurs in the Massif Central, often on the leaf surfaces also hairy representatives of the species in the Apennines are also added.
• Sempervivum tectorum var tectorum This variety has ciliated only on the edge of leaves. The leaf surfaces are smooth, only occasionally can a few short hairs are found. She is autochthonous in the central Pyrenees, in the Catalan coastal range in the Jura and the Alps to the south-eastern Alps before. The occurrence in the Mosel and Ahr valley is not sure whether they are indigenous.

Use

The Roof Houseleek is an old cultivar, this is the variety Sempervivum tectorum var tectorum. One of these cultivars has degenerated flowers whose petals are bent upward and the stamens are often degenerate. She is also depicted in the New Kreüterbuch of Leonhart Fuchs in 1543. Dazuhin there is a not distinguishable from the rosettes ago cultivar with fertile flowers. These old cultivars are very vigorous and have a Flowers actuator of up to 60 cm in height, a very expansive and flowery inflorescence and rosette diameter up to 15 cm in diameter is relatively large. Since ancient times, they were used as magic, medicinal and ornamental plant, initially for roofs, which proclaims her name. Numerous other German -language common names testify to the importance of this kind for humans. Since the Alps were developed for tourism, more locality forms came into cultivation, which have been selected for their rosette colors. They are the basis for many of today's varieties.