Lepidium draba

Hoary cress ( Lepidium draba )

The hoary cress ( Lepidium draba ), also called heart cress cress or Turkish, is a species of the genus of cress ( Lepidium ) in the family of cruciferous plants ( Brassicaceae).

Description

Vegetative characteristics

The hoary cress grows as a perennial, herbaceous plant, reaching heights of growth of 30 to 60 cm. It has a taproot and an extensive, complex system of rhizomes, which develop at the nodes buds from which enjoy numerous herd forming air rung. The stems are usually upright, vigorous, more or less at the base tight and fitting gray-haired, bald top forward and branched inflorescence in the area.

The basal leaves are short-stalked, 1.5 to 10 cm long and 1-4 cm wide, obovate, spatulate or ovate, sinuate lobed, irregularly toothed to entire, and also more or less densely gray -haired. You are in the heyday mostly dried up. The change-constant stem leaves are numerous, alternate, sessile, amplexicaul with heart - or arrow-shaped base, 1-9 (up to 15) cm long and 0.5 to 2 (up to 5 ) cm wide, hairy or bald. They have a linear- oblong, lanceolate, ovate or inverted ovoid shape.

Generative features

Schirmtraubige of inflorescence is a more or less compact, flattened on the top screen. The hermaphrodite, fourfold flowers are fragrant. The four sepals are oblong, 1.5 to 2.5 mm long, glabrous and have a white border. The four petals are white, 2-4 mm long, obovate and have a 1 to 1.7 mm long nail. The six stamens have four seitständige and two medium-sized nectar glands. The stylus has a length of 0.8 to 1.6 mm and retained on the fruit.

The 2.5 to 3.5 mm long and 3-5 mm wide fruits do not open at maturity. They are flattened, heart-shaped to almost reniform, not winged at the apex obtuse or spitzlich and without Ausrandung at the edge. The flaps are thin, grid- annoying, smooth and bare. Each fruit tray usually contains only one seed. The red-brown seeds are egg-shaped with a length of 1.5 to 2 mm.

Chromosome number

Lepidium draba is usually oktoploid with 2n = 64 (rarely 62) chromosomes, rare tetraploid with 2n = 32 chromosomes.

Ecology

The hoary cress is a perennial Hemikryptophyt and Wurzelknospengeophyt. She is a Wurzelkriechpionier and a deep-rooting.

Its flowers are inconspicuous, white, vorweibliche " nectar leading disk flowers ". Pollination is by flies; but also self-pollination takes place by the stamens bend down before flowering to scar. Blooms from May to July.

The two-seeded fruits are little pods that do not jump up when ripe, but disintegrated. They spread as granules flyer by the wind. The rapid spread along railway tracks to be due to the fact that the fruits are entrained by the air draft of the trains. However, the seed set is usually very low. The seeds are light to germinate.

Vegetative reproduction occurs abundantly through root sprouts. Therefore, the plants are often together in large herds. Under favorable conditions the balances per year can reach a growth of more than 3 square meters. The vegetative propagation is also strongly supported by the people abducted by shoot and root pieces.

Occurrence

As original home of hoary cress the Mediterranean Sea area, southern Eastern Europe, the Middle East and Central Asia are considered. From there is the hoary cress as invasive neophyte to Central and Western Europe and to North America (Canada, USA, Mexico), South America (Argentina, Chile), South Asia ( Northern India, Saudi Arabia ), South Africa, Australia and New Zealand been abducted. The hoary cress was detected in Germany for the first time in 1729, in England in 1802, in the United States in 1862 in New Zealand in 1904. In Central Europe, the spread of accelerated around 1830 and was promoted through the development of the railway network.

The hoary cress grows along roadsides, railway embankments, in docks and on scree slopes, but also on loamy fields and vineyards. It prefers warm summer and low rainfall climate and nutrient -and base- rich, humus- poor soils often. In the phytosociological system it applies in their area as part of the Central European character species of the association Cardario - Agropyretum in association Convolvulo - Agropyrion ( Halbruderale semi-dry grasslands ), but also occurs in the associations Sisymbrion and Caucalidion and in the order Onopordetalia.

Use

The seeds of hoary cress, pungent taste due to the mustard oils and were formerly used instead of pepper as spice.

System

The species name Lepidium draba was first published in 1753 by Carl Linnaeus in Species Plantarum. Frequently still is the synonym Cardaria draba (L.) Desv. be used. Molecular Systematic investigations have confirmed that the benützten to separate the two genera fruit characteristics plays no high systematic importance, and the genus Cardaria of Lepidium can not be separated. Within the genus Lepidium exist with the species around the field cress ( Lepidium campestre ) close family relationships. Next are the related Lepidium made ​​earlier also Cardaria chalepense L. and Lepidium appelianum Al- Shehbaz.