Upper flowers

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The usury flowers (tanacetum) are a plant genus within the family of the osprey (Asteraceae). The 150 to 160 species thrive in the temperate areas of the northern hemisphere.

Description

Vegetative characteristics
Tanacetum species are mostly perennial, very rarely annual, herbaceous plants or rarely semi-bushes or shrubs. Many species lumber more or less strongly at their base. They form rhizomes as survival organs. They are usually aromatic smelling plants.

The alternately arranged foliage leaves are stalked or unstacked. The leaf spreads are rarely simple, usually they are feathered.

Generative characteristics
Predominant are total flowering positions composed of cup-shaped partial flowering positions (often in the form of an umbrella rasp), rarely only a single cup-shaped flowering position is present. The flower baskets have a diameter of rarely 3 to, usually 5 to more than 22 millimeters. The (rarely 20 to) usually 30 to more than 60 wrapping leaves are in (rarely two) usually three to five rows. There are no chaff leaves. The flowering baskets contain 10 to over 21 tongue flowers and 60 to over 300 tube flowers. The mostly female, fertile or sterile tongue flowers are white or yellow. The twilight, fertile tube flowers are yellow.

The Achenes are usually five to ten ribs (four to over twelve ribs). The pappus consists of only a skinned, crown-shaped hem, rarely no pappus is present.

Chromosome sets
The basic chromosome number is x = 9. There is often polyploidy.

Ingredients

Pyrethrum
The insecticide Pyrethrum is obtained from the dried flowers of Tanacetum species by crushing or extraction with solvents. The ‘Montenegrin or Dalmatian insect powder’ is obtained from the Dalmatian insect flower, insect powder (Tanacetum cinerariifolium, Syn.: Chrysanthemum cinerariifolium, Pyrethrum cinerariifolium), while the ‘Armenian, Persian or Caucasian insect powder’ is obtained from the Caucasian insect flower (Tanacetum coccineum, Syn.: Chrysanthemum coccineum, Pyrethrum roseum, Pyrethrum carneum). The Pyrethrum species were a genus of their own, but are now incorporated into the genus Tanacetum.

Pyrethrum-producing plants are preferably grown in or exported from Africa (for example Tanzania, Kenya), Central America (for example Ecuador, Colombia), New Guinea and Japan.

Nomenclature and distribution
The genus Tanacetum was erected in 1753 by Carl von Linné in Species Plantarum, Tomus II, page 843. Synonyms for Tanacetum are: Balsamita, Gymnocline, Pyrethrum, Pyrethrum, Spathipappus.

The main distribution area of the genus Tanacetum is in the Holarktis. The Tanacetum species thrive in the temperate areas of the northern hemisphere in Eurasia, North Africa and North America. Some species are grown worldwide.

There are 150 to 160 species of Tanacetum (selection):
Tanace