Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Brassicales
Family: Resedaceae
Genus: Reseda
Species: R. luteola
Binomial name: Reseda luteola
Common name: Dyer's Weed, Weld, Dyer's rocket, Yellow weed, Dyer's mignonette, Mignonette, Wild mignonette
Reseda luteola is a biennial, plant species native to north-eastern Africa (i.e. Egypt and Libya), southern Europe (i.e. Portugal, Spain, Albania, Bulgaria, Greece, Italy and Yugoslavia), western Asia (i.e. Afghanistan, Cyprus, Iran, Iraq and Turkey) and Pakistan.
In New Zealand it is an introduced species and is classed as a weed It is found in Auckland, Bay of Plenty, Taranaki and Wellington in the North Island. It is found throughout the South Island especially in Central Otago.
It is a tall (1.5m), erect, plant with a flower spike that is heliotropic (turning to the sun). The flowering stems have many narrow leaves and several flowering spikes. Flowering occurs from October to January. The stems are unbranched. The flowers are yellowish-green and are on long terminal pointed spikes. They have 4 sepals and many stamens (20-24). The fruit is a flattened capsule which is trilobed. The seeds are round, smooth and are a shining black.
Reseda luteola was the most widely used source of the natural dye known as weld. The plant is rich in luteolin, a flavonoid which produces a bright yellow dye. The yellow could be mixed with the blue from woad (Isatis tinctoria) to produce greens such as Lincoln green. The dye was in use by the first millennium BC. Use of this dye came to an end at the beginning of the twentieth century, when cheaper synthetic yellow dyes came into use.
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The plant inflorescence tips in the photo below are growing upward, this was because at some time the plant was bent sideways. This growing effect is called geotropism. It is the directional growth of parts of plants in response to the force of gravity. The upward growth of this plant is called negative geotropism. The downward growth of roots is called positive geotropism.
Thanks to Wikipedia for text and information http://creativecommons.org/licenses/by-sa/3.0/
