Botanical Accuracy: Teasels tousled with thistles

Friday, January 31, 2014

Teasels tousled with thistles

Thistles are such familiar plants to most of us, these spiky, thorny, sharp-leaved plants with fuzzy purple or pink, or less commonly yellow, flower heads. We love them and hate them, as they are both beloved and tasty plants (artichoke, the Scottish symbol) and less liked since they can be weedy and sometimes invasive. They get around with their little fruits attached to a pappus-umbrella of hairs that act like a parachute for long-distance dispersal. Thistles are well-known and common in popular media and literature.

'Thistle clipart' search on Google yields this result - these are all thistles.
Screenshot by BotanicalAccuracy.com.

Most of the plantswe call thistles belong to Asteraceae (the sunflower family) and form their own group (a tribe called Cardueae (=older name) or Cynareae). In this group you have genera and species such as Arctium (burdock), Carduus, Carthamus (safflower), Centaurea (knapweeds, corn flower, star thistle), Cirsium, Cynara (artichoke, cardoon), Echinops (Globe thistle), Onopordum, and Silybium (milk thistle).

A typical thistle flower looks like this:

Thistle, probably Cirsium.
Photo from United Kingdom, by John Cooke on Flickr (Creative Commons).

The problem is the teasels (Dipsacus). They are in the family Dipsacaceae, not too far away from Asteraceae's thistles, but certainly not true thistles, but they look a bit like them and get confused with them a lot. Teasels also have large heads of small flowers and are plants that look ferocious with spines. The teasel itself got its name from that the flower heads were used to tease out the wool before spinning (carding). Several teasels are invasive in the United States and you often see them along highways in disturbed ditches and on road banks. Their flowering heads dry beautifully into gorgeous botanical stalks for flower arrangements.

A typical teasel look like this:

Teasel, Dipsacus.
Photo by Bev Currie on Flickr (Creative Commons).

So, can you tell teasels and thistles apart? Thistles have many (involucral) bracts below the flower head that form a cup below the flowers. In teasels, there are just a few long bracts that stick out below the flower head. The teasels have lots of sharp parts in the actual flower head, so the flower head looks like a spiny ball the whole season. In thistles, the bracts below the flower stays, but there are no persistent spiny parts inside among the flowers themselves. The fruits, which are little nut-like, single-seeded achenes have a feathery pappus for wind-dispersal in thistles, but are naked in teasels. Good teasel photos are available on invasive.org.

As usual for some of these misunderstandings and misapplications, the stock photo market is abundant with incorrectly identified plants. There seems to be no taxonomic quality control of what photos actually show and what they are labeled on places like iStockphoto, Colourbox, and Getty Images. For plants this is especially disturbing since commercial companies and media buy representative photos of that they think are thistles, poppies, and chamomile, and then use them in good faith. Unfortunately, this is a major reason why botanical inaccuracies are propagated and also the media companies paid for something they didn't got. (The problems with chamomile images are especially abundant, but that is for a later post.)

Here are some teasels that are labeled as thistles on stock photos for sale:

Teasels presented as thistles on gettyimages (link).
Screenshot by BotanicalAccuracy.com.

More teasels listed as 'thistle plant', this time on Colourbox (link).
Screenshot by BotanicalAccuracy.com.

Dried flowering heads sold as 'dried thistle' by Country Creations (link).
Screenshot by BotanicalAccuracy.com.

What is Botanical Accuracy?

Would you care if someone called a cat 'a mouse' in the description of a medieval painting?

Would you care if someone served you horse meat, but said it was beef? I bet you would.

Would you care if the wrong chemical was listed in the ingredient list of your shampoo or cereal?

Would you care if you bought one plant, but got another?

Would you care if there were species or ingredient mistakes in advertising, menus, herbal pills, and such things?

Would you care if books on plants are illustrated with the wrong plants?

If so, here is the place for you to read about such problems in the world of plants and plant products, where unfortunately such mistakes, inaccuracies, and problems are not uncommon. This is usually due to lack of botanical knowledge or expertise, or sometimes because of plain ignorance.

Inaccuracies are common when it comes to plants, because it seems like we humans care to learn less about green things like trees, flowers, and herbs than we care to learn about animals, even when we eat plants, paint them, plant them, extract their chemicals, or use them in numerous other ways.

Without plants in the world you and I certainly would be dead. Some plants can also kill you with their toxins, so it is best to know which plant is what species. Time to learn some botany!

About mistakes, inaccuracies, and errors

Science is a process of gaining knowledge and understanding of the world around us. It is a never-ending process, and what we think are true facts today might change tomorrow. In science we are aiming for having the best understanding possible today based on what we and our predecessors have learned until now.

This means that what is botanically accurate from a scientific viewpoint might (and will) change. Other experts in the field of botany know a lot more about their particular research plants than I do. New scientific findings and conclusions are being published every day. This is just normal and part of the scientific process; we improve on our knowledge all the time.

The important thing is our willingness to continuously aim for botanical accuracy and the highest scientific standards in our use of names and facts. When things are wrong, let's correct them. Let us not perpetuate wrong botanical knowledge by accepting its incorrect use on commercial products, in everyday language, or in other parts of our contemporary cultures. Through scientific education and specific corrections we will improve botany and science for everybody, in supermarkets, restaurants, and garden centers.

It is the perpetuation of incorrect facts that are the problem, not the need for correction. Everybody makes mistakes, and everybody learns, throughout their lives. We need words to be able to communicate and talk about things, so let's use the right words and the right species names.

Undoubtedly there will be mistakes and errors on this blog, or things that need to be updated. If you want to get in touch, please e-mail me at botanicalaccuracy at gmail.com. If you see a mistake on this blog, e-mail me with the link to the post and an explanation what is incorrect and should be updated. If you represent a company and want to get in touch, please use the same e-mail address.