Plant families: Asteraceae

Asteraceae Family

Key Words: Composite flowers in disk-like heads.

This family was previously known as the Composite family-Compositae.

Asteraceae plants are everywhere. From sunflowers that make the sky look even bluer to the lettuce that’s in your salad, you come into contact with members of this family regularly. The Asteraceae family is one of the largest plant families with several sub-genera within, such as the genera Artemisia and Arnica.

Mostly used for flowers and food, some members of the Asteraceae family have been used in folk medicine for centuries. Containing terpenoids and flavonoids, they produce many beneficial effects on our bodies. Some though may be allergic to these compounds, so a bit of general knowledge and information is necessary.

Asteraceae are recognised mainly by they composite flowers. though they look like a single flower, imagine a sunflower, it is actually a disk containing hundreds of single flowers known as a composite flower.

What is a composite flower?

Photo of aster by Skyler Ewing on

A word from Wikipedia about composite flowers:

In plants of the family Asteraceae, what appears to be a single flower is actually a cluster of much smaller flowers. The overall appearance of the cluster, as a single flower, functions in attracting pollinators in the same way as the structure of an individual flower in some other plant families. The older family name, Compositae, comes from the fact that what appears to be a single flower is actually a composite of smaller flowers.

The “petals” or “sunrays” in a sunflower head are actually individual strap-shaped flowers called ray flowers, and the “sun disk” is made of smaller circular shaped individual flowers called disc flowers. The word “aster” means “star” in Greek, referring to the appearance of some family members, as a “star” surrounded by “rays”. The cluster of flowers that may appear to be a single flower, is called a head. The entire head may move tracking the sun, like a “smart” solar panel, which maximizes reflectivity of the whole unit and can thereby attract more pollinators.

On the outside the flower heads are small bracts that look like scales. These are called phyllaries, and together they form the involucre that protects the individual flowers in the head before they open. The individual heads have the smaller individual flowers arranged on a round or dome-like structure called the receptacle. The flowers mature first at the outside, moving toward the center, with the youngest in the middle.

The individual flowers in a head have 5 fused petals (rarely 4), but instead of sepals, have threadlike, hairy, or bristly structures called pappus, which surround the fruit and can stick to animal fur or be lifted by wind, aiding in seed dispersal. The whitish fluffy head of a dandelion, commonly blown on by children, is made of the pappus, with tiny seeds attached at the ends, whereby the pappus provides a parachute like structure to help the seed be carried away in the wind.

Photo of dandelion seeds (pappi) by Anthony on

Getting to know the Asteraceae Family

Courtesy of Thomas J. Elpel

This article by is a great resource for the Asteraceae family.

Photo of daisies by Aaron Burden on

Members of the Asteraceae Family

Courtesy of

Photo of calendula by Mitchell Luo on
American medicinal plants New York,Boericke & Tafel,c1887.

Asteraceae Medicinal Actions

Asteraceae or Compositae is an exceedingly large, annual and widespread family of flowering plants. They produce secondary metabolites, such as flavonoids and terpenoids which have lots of effect on our body. Many of the Asteraceae family are plants which have been used in traditional medicine. Many studies have shown the effects of Asteraceae family plants or their extract on immune-mediated diseases, especially their anti-inflammatory effect.
Members of this family can have these medicinal actions:

Diuretic, drawing, expectorant, draining, antiparasitic, respiratory support, gastric support, blood regulation, antibacterial, help with microbial infections.

Asteraceae: A Cautionary Tale

Many Asteraceae members contain metabolites called sesquiterpene lactones which, in those allergic, can cause inflammation, skin irritation and sensitisation. This same metabolite has been shown beneficial in treating cardiovascular disease and cancer, as well as a host of other disorders from diarrhea to influenza,,. It is important to know the information, so I recommend reading these articles in order to get the full picture regarding this metabolite.

Beware the Asteraceae allergy:

The Asteraceae representatives consist of diverse secondary metabolites, which exhibit various advantageous effects in humans. In particular, sesquiterpene lactones (SLs) may cause sensitization resulting in skin irritation and inflammation. In this study, we tried to reveal the allergenic potential of several Asteraceae species. The Asteraceae-related allergy symptoms involve eczema, hay fever, asthma, or even anaphylaxis. Furthermore, the evidence of severe cross-reactivity with food and pollen allergens (PFS) in patients sensitive to Asteraceae allergens have been announced.

Asteraceae for the win:

Studies of folk medicines implicate sesquiterpene lactones as the active ingredient in many treatments for other ailments such as diarrhea, burns, influenza, and neurodegradation. In addition to the anti-inflammatory response, sesquiterpene lactones have been found to sensitize tumor cells to conventional drug treatments.
Photo of bee on sunflower by Karolina Grabowska on
Photo of artichoke flower by Pixabay on

Poisonous Plants: Tansy

Tansy is beautiful. But I have a love/hate relationship with tansy. The flowers are beautiful, aromatic and the plant is a breeding place for ladybugs.

The ladybugs have taken up residence in my tansy (Tanacetum vulgare) plants.

I love seeing the whole life cycle of ladybugs in my tansy plants. But be warned, the tansies will take over your garden, are near impossible to get rid of and can be dangerous. Containing thujones (the same component that gives Absinthe its bad name), as well as other volatile oils, which can cause convulsions, liver and brain damage and can be lethal in the right amount. It is used in herbal medicine, but should only be used by an expert.

And tansy’s dark side is darker than most – it’s literally a killer. Despite historically being commonly used as a flavouring, bitter-tasting tansy contains a toxic essential oil that can cause liver and brain damage and even kill humans and other animals. On a less lethal level, it can also prompt an allergic reaction in some individuals when touching the leaves.

History of uses:

Tansy has a long history of use. It was first recorded as being cultivated by the ancient Greeks for medicinal purposes. In the 8th century AD it was grown in the herb gardens of Charlemagne and by Benedictine monks of the Swiss monastery of Saint Gall. Tansy was used to treat intestinal worms, rheumatism, digestive problems, fevers, sores, and to bring out measles.

During the Middle Ages and later, high doses were used to induce abortions. Contradictorily, tansy was also used to help women conceive and to prevent miscarriages. In the 15th century, Christians began serving tansy with Lenten meals to commemorate the bitter herbs eaten by the Israelites. Tansy was thought to have the added Lenten benefits of controlling flatulence brought on by days of eating fish and pulses and of preventing the intestinal worms believed to be caused by eating fish during Lent.

Tansy was used as a face wash and was reported to lighten and purify the skin. In the 19th century, Irish folklore suggested that bathing in a solution of tansy and salts would cure joint pain.


Tansy is used as an excellent insecticide and anti-parasitic, but must be used with caution. Please do your research and rather use wormwood and black walnut as your antiparasitic.

Enjoy this mildly obscene video…

Ladybugs goin’ at it in the tansy…

Articles about tansy:

Asteraceae plant family resources:

Identifying a new plant

Using these resources, one is easily able to identify its genus and species:

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