Showing posts with label Asteraceae. Show all posts
Showing posts with label Asteraceae. Show all posts

Tuesday, November 29, 2016

Anatomy of artichoke heads

This educational and interactive image from the artichoke company Ocean Mist Farms in California on the Anatomy of an Artichoke made me scratch my head. It is stated on their website as the largest artichoke producer in the US, and has a long history growing fresh vegetables of many kinds. On their website they provide a nice interactive feature where you can slide a slider across and see the inside, the anatomy, of an artichoke:
Screenshot of Anatomy of an Artichoke on the Ocean Mist website.
Screenshot by Botanicalaccuracy.com, 29 Nov 2016 (fair use).

 Unfortunately, the botanical facts about the artichoke head are not anatomically correct.
 The text states:
"You may be interested to know that the Artichoke is actually the bud of a plant from the thistle family and at full maturity, the plant grows to a width of about six feet and a height of three to four. If not harvested from the plant, the bud will eventually blossom into a beautiful, blue-violet flower, which is not edible. The bud contains the Heart, the delightful, meaty core of the Artichoke, and is topped by a fuzzy center, or choke, which is surrounded by rows of petals, which protect the Artichoke Heart. With their tiny thorns, the Artichoke’s petals reveal their thistle heritage."
The artichoke is indeed a type of giant thistle, and if you let it flower it will open up to show a flower head similar to thistles, just much larger.  But note the word HEAD, which is used for flower arrangements (inflorescences) that have tightly packed and unstalked flowers.

The thistles are part of the sunflower family, the Asteraceae, which is also the home of dandelions, marigolds, tarragon, mugwort, chicory, lettuce, chrysanthemum, and dahlias.  All of the species in this family have tiny flowers collected in a cup- or saucer-like head (capitulum), that is surrounded on the lower side by bracts (modified small leaves).  The flowers are small and tightly packed, often with tubular narrow (disc) flowers in the center and sometimes with longer, flattened (ray) flowers along the edge, like in a sunflower. One group of species have only ray flowers, like in dandelions.  In thistles, there are only tubular disc flowers, and the bracts are long and initially covers the whole sides and top of the head.

So, in their effort to educate the public about the fascinating anatomy of the floral heads of artichokes, Ocean Mist Farms manages to really mix things up.  Here is the corrected version of their image:
Corrected version of the screenshot of Anatomy of an Artichoke, original from Ocean Mist Farms. Modified image by Botanicalaccuracy.com. (fair use, cc-by)

Their text should read something like this instead:
"You may be interested to know that the Artichoke is actually the YOUNG FLOWER HEAD of a plant from the thistle family and at full maturity, the plant grows to a width of about six feet and a height of three to four. If not harvested from the plant, the HEAD will eventually blossom into a FLOWER HEAD WITH beautiful, blue-violet flowerS, which ARE not edible. The HEAD contains the Heart, the delightful, meaty core of the Artichoke, and is topped by a fuzzy center OF YOUNG FLOWERS, or choke, which is surrounded by rows of BRACTS, which protect the Artichoke Heart. With their tiny SPINES, the Artichoke’s BRACTS reveal their thistle heritage."
It is not too late to learn and this is not an uncommon mistake in the food world. Hopefully they fix this information soon.  If you want to dig deeper into the anatomy of artichokes, I recommend this post on the Botanist in the Kitchen blog.
(Thanks to RO for sending me this example of botanical inaccuracies in commercial products and companies.)

Sunday, August 28, 2016

Bad taxonomy can kill world records


Or, When the world's tallest dandelion isn't a dandelion. 
The motto of The Guinness World Records is OFFICIALLY AMAZING.  And that it is, officially amazing, but not only in the sense that they might think.  When I was a kid in Sweden I loved their orange-colored book, (1975 edition, maybe?) and I read everything in it, and stared at the photos of the man with the longest nails (how did he eat?) and the largest cat, amused and entertained and informed.  Now I get to come back to this memorable source of trivia, but this time for a botanical and work-related reason.

The world record for the tallest dandelion is nearly a foot taller than most people was found by two Canadians 2011.  They had their dandelion verified by two experts in Canada (see below) and accepted by the Guinness office as an official world record. From the Guinness website:
"The tallest dandelion measured 177.8 cm (70 in) and was found by Jo Riding and Joey Fusco (both Canada) in Ontario, Canada. The dandelion was measured on 12 September 2011. The dandelion was found on 4 August 2011 and was unofficially measured at 76 in. The dandelion was then officially measured by NutriLawn and The Weed Man on 12 September 2011 when it had dried out and was measured as 70 in."  (link)
There is no photo of the plant on the record website, unfortunately, but there is a youtube video uploaded by JO Riding, telling the whole story of finding and measuring of the plant. 

By the time the plant was measured it had been dried for weeks, but you can clearly see in the video that it had many leaves on its stem, and that there were several flowers on the top of several branches.  There is no clear taproot and no rosette of basal leaves. To conclude, this was no dandelion. (And just to confirm, the Canadian botanist Luc Brouillet who wrote the Flora of North America treatment for dandelions, agrees with this conclusion.  And he should know.)

There are many species related to dandelions (genus Taraxacum) that are similar to dandelions in having yellow flower heads and 'puffball' seed heads that eventually blow in the wind, but they are not dandelions, they below to other genera.  All of these are members of the sunflower family (scientific name Asteraceae), and dandelion and its relatives are members of the Cichorieae (aka Lactuceae) subgroup (=tribe) that has members with milky sap (latex) that you can see if you break a leaf or stem.
Dandelion (Taraxacum)  from Lindman's Bilder ur Nordens flora, Public Domain.
Here is a real dandelion, a species in the genus Taraxacum. All the leaves are in a basal rosette at the base, and from the middle of the rosette a light-colored, hollow stem comes up and holds just one flower head. There is a big taproot under the plant that can survive year to year, and that is why they are so hard to get rid of - you have to dig them out. It is a perennial problem - cut the flower head stalk off with your lawn mower and it just sends up a new one from its low stem and perennial root.
Milk Thistle (Sonchus arvensis), illustration from
Otto Wilhelm Thomé Flora von Deutschland, Österreich und der Schweiz (1885), Public Domain.
And here is a weedy look-alike, but check out the differences in the position of the leaves and the branched stems with many flowers.  This is a milk thistle (Sonchus), which is probably what was reported from Ottawa as the world's tallest dandelion. It is unclear if the two Ottawa companies that certified its height, Nutri-Lawn and Weed Man, also certified its species identity, but both companies should be very familiar with dandelions and other weedy species.  Nutri-Lawn is a lawn care company specializing in "ecology friendly lawn care" and Weed Man, another gardening company has a very funny green man as their home page mascot.  It might be that Guinness World Records didn't ask for species verification. 

And then there was this UK news story this summer, Man accidentally grows the 'world's tallest dandelion plant'
Screenshot from The Telegraph (UK) website (link) by BotanicalAccuracy.com, 18 Aug 2016. Fair use.
" Mr Daniels is keen to get his dandelion officially measured as soon as possible before it starts to wilt or dry out. He added: "I'm not a gardener hence why I'm growing a dandelion, it is just luck that it has grown so big as I have done nothing to it over then let it grow." A Guinness World Records spokesman said: "We invite the claimant to make an application via our website in order for us to be able to ratify the achievement."
This is not a dandelion either. All those little flower heads in a strongly branched inflorescence and the leafy stems with bluish-green leaves with light-colored mid veins indicate that this seems to be Lactuca, maybe prickly lettuce (Lactuca serriola). Lactuca is the same genus as your supermarket lettuce, but this is a wild species. This is how Lactuca looks like. Some species have blue petals, other yellow.
Wild lettuce or prickly lettuce  (Lactuca serriola) from Köhler's Medizinal-Pflanzen, Public Domain.
For the record, WeedZilla with a height of 12 feet isn't the World's tallest dandelion either, that is something else in the sunflower family. It is a giant weed indeed, but not a dandelion. Sorry.   

The strange thing is that dandelions are not hard to identify with certainty if you know what to look for.  The book Foraging & Feasting: A Field Guide and Wild Food Cookbook by Dina Falconi includes a great 'plant map' illustrated by Wendy Hollender of all the good key characters for dandelions. You can also read about dandelion's great benefits and ancient ethnobotanical uses.  

I am not writing this to point out that people identify plants wrong.  That happens all the time, and is just a matter of education, curiosity, and interest in plants that live around us.  There are plant identification forums online with over 50 000 members, and the fact that people are curious about strange, cool, and giant plants is a great thing.  People should ask about plants, and let themselves be amazed by them. It is OK to know little, especially if you want to know more and satisfy your curiosity.

The problem is the fact checkers at Guinness World Records who put themselves and their company into this embarrassing situation.  First, they should make sure they actually have the right species in hand. The easiest for this is to have photos of the plant while alive, you know 'pics or it didn't happen!'.  They should also require a pressed specimen of the plant, not just air dried, but pressed between newspaper sheets so it is preserved and flat.  That way specialists can look at it later and say: "yep, you have a true dandelion!", or "sorry, that is a milk thistle, nice plant anyway!"  This is called vouchering and is standard practice for all species reports, including DNA testing, species inventories, herbal plant identification, and chemical analysis.  There is no reason why Guinness World Records could not implement this, and have a botanist verify the species identification and have a link to an actual preserved specimen (the proof). 

So, what is truly the record for world's tallest dandelion? Well, there are reports out there that show real dandelion (Taraxacum species). So far, the record seems to be the dandelion found by a Norwegian boy, Bjørn Magne, with a 108 cm (42 inches) long flower stalk, and reported to World Record Academy in 2007.  Before then, the Guinness World Book of Records had a 39-inch tall Swedish dandelion from 2003 as a record holder. The Nordic countries seem to be great for further giant dandelion exploration.  To inspire you, here are some dandelions on Iceland's lava-covered plains in the never-setting sun of Nordic summers. 
Dandelions on Iceland. Photo and copyright by Didrik Vanhoenacker (thanks for letting me borrow the photo).
PS.  Thanks to Asteraceae specialist Torbjörn Tyler, field biologist-on-call Didrik Vanhoenacker, professor emeritus Arthur Tucker, and dandelion taxonomist Luc Brouillet, who all helped and gave feedback on research for this blog post.

Friday, July 10, 2015

No, you are not allergic to pretty flowers...

During this year's pollen season, the usual misinformation about pollen allergies crop up and grow fast in the media, online as well as in print.  Sneezing and astmathic people and their medications are often incorrectly associated with colorful flower imagery, when in reality very few people are allergic to the flowers that most of us know and love. But to advertising people, small tiny green flowers with dangly stamens might not be as photogenic as make-a-wish dandelion fruits and fields of flowering canola.
These ox-eye daisy flowers in this Shutterstock image on the Rocky Mountain Allergy Asthma Immunology website has absolutely nothing to do with pollen allergies. They are just pretty flowers. 
(Screenshot image by BotanicalAccuracy.com, source.)
A screenshot from a quick search on the keywords 'pollen allergy' on the photo website Shutterstock, shows an abundance of photos of insect-pollinating plants, flowering fields, and dandelion fruiting heads which has nothing to do with pollen allergies.  Some photos get it right but not the majority. (Screenshot by BotanicalAccuracy.com, source.)

Pollen, which are special small cells in seed plants that contain the male sex cells (no, it is not gross, just the fact), are produced in flowers and when the pollen lands on the female part of a flower or cone (the landing platform is called a stigma), the pollen germinates and a pollen tube grows into the female style and down into the ovary where it can fertilize the plant's egg cell and make a seed. This is not gross, just the facts, and in fact, if there were no pollen, there would be no fruits, no flowers, no seed plants. Seed plants are those that set seed, so that means conifers and flowering plants, but not ferns and mosses, because they have spores instead. Not all pollen causes allergies and neither does all spores.
Pollen grains from many different plant species shown in a photo from a Scanning Electron Microscope. (Public domain image from Dartmouth College Electron Microscope Facility via Wikimedia Commons, source.)


So, how does the pollen gets transported from the male to the female part in the flower? Most plants use animals as transport helpers (for bee pollination, etc.), but some plants have wind-pollination.  If you are adapted to use wind as the pollination method, then you are going to have some problems to overcome - first, wind is kind of random so you don't know where your pollen would end up, so you better make LOTS of pollen; second, you don't want your pollen to stick to anything that isn't the right stigma, so it needs to be dry and smooth and fly easily; and third, you need to make your pollen-sacs hang out far into the air without interference from large petals, so you can disperse your pollen with every little wind burst. These three evolutionary adaptations are seen in many wind-pollinated plants.  So, these plants produce an copious masses of dry, easy-flying pollen from small flowers with hanging pollen sacs.  This is exactly how birches, ragweed, grasses, walnuts, mugwort, elms, pigweeds, cottonwoods, and hickories spread their pollen around.  And these plants are the ones people who suffer from pollen allergies are allergic to (see caveat below).
Flowers of a grass, showing stamens with pollen sacs hanging out and spreading their light dusty pollen into our eyes and noses (and to other grasses). (Creative Commons photo by Dave Kleinschmidt, source)
Many people think they are allergic to goldenrod, this common, yellow-flowered fall flower, but it is insect-pollinated.  Plants that are pollinated by insects have 1) something that attracts the insect to the flower, usually sweet smell and bright colors, 2) sticky pollen that gets stuck on the insect, and 3) small amounts of pollen.  You can easily tell if a plant is insect or wind-pollinated by looking at its flower and checking if any pollen flies out in the air if you shake it (this only happens in wind-pollinated flowers).  There are also plants pollinated by mammals, birds, and other small animals, as well as water, but those are more rare.  In North America, the hummingbirds are the only birds that pollinate flowers.
VividLife illustrates their POllen Allergy Awareness article with a nice, invasive thistle, pollinating insect included.  Of course, it has colorful small pink petals (in a big flower head), sticky pollen, and is not something that easily causes pollen allergies. Another blatant example of wrong imagery in the pollen allergy area (Screenshot by Botanical Accuracy, source)
 So, when your neighbor says that he can't go outside because the dandelions are flowering, or there is a newspaper article about hay fever illustrated with a pretty flower, or your oldish aunt says she is allergic to the pollen of cut flowers in a vase, they will most likely be very wrong.  (Some people are allergic to the smell of pretty flowers, but that is different.)  Still, the misconceptions are flying like airborne wind-dispersed pollen in advertising, news media, and around lunch tables.
News article about herbal remedies for hayfever in The Epoch Times, May 21-27, 2015,
illustrated with a sneezing girl in front of a flowering canola field (which is not a wind-pollinated flower),
and with dandelion fruits blowing away below. (Photo by BotanicalAccuracy.com)
An other prevalent misconception shown in allergy imagery, even on the websites of medical and pharmaceutical companies based on science, is the (non-existent) connection between dandelions' fruiting puffy heads and allergies.  No, you are not allergic to flying dandelion parachute fruits and seeds, despite all those photos and ads showing exactly this connection.
Article from Mass Lunch & Allergy PC illustrated dandelion heads under the heading Pollen Allergy. Please note that the fruiting dandelion head not only has no pollen in it, it is also a fruit, not a flower. The grass would be the allergen to most hay fever suffers. (Screenshot by Botanical Accuracy, source)
In this image below, there isn't even one potential flower and no pollen source at all:

Freedom Home Care has an article called How to Keep Seasonal Allergies Under COntrol, and it is 100% illustrated with a no-pollen part of an insect-pollinated plant - Dandelion fruiting heads, again. Such misuse of images just creates confusion and makes the public afraid of real nature. (Screenshot by Botanical Accuracy, source)  

 So, why does these image mistakes matter?  It is just a picture, right?  Well, they matter a lot.  The public reads the information and associates the allergies with the images that are used to illustrate them.  Allergies means medical problems (bad stuff). We start to think allergies when we see canola fields, blowing wishes with dandelion heads, and pretty flowers.  It is 'guilty by association' and just more of the fear of nature that is spread around in media.  Fact checking should not only be for the words but also for the images that goes with the words. Some allergy doctors and pharmaceutical companies are just as guilty as photo databases in this area.

Caveat: This blog post is based on what most people are allergic to that react to pollen.  You could become allergic to nearly anything, so a small percentage of people could be allergic to tulip pollen, rose petals, and goldenrod pollen, but that is very, very rare.  When testing for allergies, it is the wind-pollinated plants that count.

Links for more information:
American College of Allergy, Asthma & Immunology: Pollen Allergy: Be aware that this webpage has some overly simplistic descriptions about the biology and biodiversity of plants.  For example: "Pollen is very fine powder that comes from trees, grasses, flowers and weeds." and "When a plant begins to flower, its pollen goes into the air."  They need a biologist fact checker.  No need to make things so simple fo the public that is becomes wrong.

Many thanks to KS for medical allergy testing information.

Saturday, October 18, 2014

Chamomile, what flower is on your tea box?

What do you think - does this chamomile tea box from STASH show chamomile flowers or something else?
  The medicinal plant chamomile has been used since ancient times for medicinal uses, especially as a calming and sleep inducing tea.  Chamomile is usually one of two similar-looking species, Roman chamomile (Chamaemelum nobile) or the more common German or wild chamomile  (Matricaria chamomilla). These species have many common names and also many scientific synonymous names, so I am listing some of them below.

So, what is the problem?  Well, there are many species in the sunflower family that look like white daisies with a yellow center, like both of the chamomiles have. So the companies that make chamomile tea packaging seems to have a horrible time putting the right species on the box.  Even worse is the stock photo market where a lot of 'chamomile tea' photos show something totally different than one of the two chamomile species.

Why does this matter?  Even if plants are similar in shape and color, they can have different chemistry.  Many times an edible plant may have a toxic look-alike.  If companies can't even bother putting the right plant on the label, can you trust them to check what is really in that bulk sample of dried leaves and flowers they are selling and want you to steep and drink and then sleep calmly on?  Maybe not... 

So, how does the two true chamomile species look like? First, the 'flower' of a chamomile is a whole flower head.  It is a member of the sunflower family, Asteraceae, and just like its relative the sunflower in each flower head there is a circle of outer small ray flowers (white), and in the flat center is an area of disk flowers (yellow) that look like small yellow tubes.

Here is German chamomile (Matricaria chamomilla, some older names are Chamomilla chamomilla, Chamomilla recutitaMatricaria recutita and Matricaria suaveolens):

German chamomile.
Photo by kallerna on Wikipedia, Creative Commons license.
German chamomile, in Köhler's Medizinal-Pflanzen on Wikimedia, public domain.
Note how the leaves of German chamomile are divided into many narrow segments, and how the flower head is hollow and uplifted in the center with age, and how the white ray flowers along edge becomes vertically pointed downwards with age.


Here is Roman chamomile (Chamaemelum nobile), a very similar species that previously has been called Anthemis nobilis.
Roman chamomile, in Köhler's Medizinal-Pflanzen on Wikimedia, public domain. 
The Roman chamomile also have finely dissected leaves and a central part of the flower head that is lifted up.

The most common mixup when it comes to photos and other illustrations of chamomile is with the oxeye daisy, Leucanthemum vulgare. It has very different leaves that are whole and with a serrate edge.  The flower heads are flatter and the ray flowers are a lot larger and longer.  This species is also often unbranched or just branched from the base, but Roman and German chamomile are often very much branched.
Ox-eye daisy, from Lindman's flora, now in the public domain.
Fleabane is another species you see mixed up with chamomile sometimes.  It has many, many more ray flowers and each white ray is a lot narrower than a chamomile or ox-eye daisy.
Fleabane, Erigeron annuus, with a branched inflorescence, whole leaves, and flower heads with many, many white ray flowers. Photo by Enrico Blasutto on Wikimedia, Creative Commons license.
The easiest way to tell these species apart is to look at the flowers in the flower head and the leaf shape - here is an overview of the good characters to tell them all apart:



Common name
German chamomile
Roman chamomile
oxeye daisy
fleabane
Accepted name
Matricaria chamomilla
Chamaemelum nobile
Leucanthemum vulgare
Erigeron sp.
Older names
Matricaria recutita
Anthemis nobilis
Chrysanthemum leucanthemum
Erigeron annuus and E. strigosus are common species)
Leaf type on stem
finely dissected into small, long narrow lobes, fern-like
finely dissected into small, long narrow lobes, fern-like
simple, whole leaves wider towards the apex, edges with irregular teeth, leaves clasping stem
whole, lance-shaped to oblong, with serrate edge
Flower heads per plant
ca. 8–120 per plant, stem heavily branched
ca. 3-20 per plant, branches many
ca. 1-10, branches few and flower heads long-stalked
5–50+ per plant, branches many
Number of white ray flowers per head
ca. (10-)14-26
ca. 13–21
ca. 13–34
ca. 80–125, very thin and narrow
Ray (white) flowers on old flower heads
bending down under the flower head
bending down under the flower head
spread outwards, horizontal, sometimes downwards (wilted look)
spread outwards, horizontal, or coiling upwards
Yellow center in middle of flower head (= all disk flowers)
raised like a dome
raised like a dome
flat or sunken inwards
flat or slightly dome-shaped, often slightly sunken in center


So, who got it wrong and needs to fix their packaging illustrations? 
Royal herbal tea infusions show oxeye daisy on their chamomile tea. 


Stash's non-organic chamomile tea unfortunately shows a fleabane plant. Flea bane has been used for, you guessed it, remove fleas and other parasites on our bodies and clothes. Photo by BotanicalAccuracy.com.

Do any teaboxes show the right chamomile?  
Alvita Chamomile tea box with real chamomile on it.
Stash's organic chamomile tea shows nice real chamomile on it.
Traditional Medicinals also gets it right with their organic Chamomile tea.  Here is the right thing.

And then we have the world of stock photo inaccuracies, which seems to be a never-ending subject.  The lack of quality control of stock photos is rather astounding.

Dreamstime is selling two photos labeled as 'Cup of herbal tea with chamomile flowers'. Sorry, that is ox-eye flowers. Screenshot by BotanicalAccuracy.com.



And then we have the mystery plant.  On Tom's of Maine's toothpaste 'Botanically Bright, with natural chamomile', there is a flower head that is not chamomile, but something else in Asteraceae, and leaves that are neither chamomile, fleabane, nor oxeye daisy.  I wonder what it might be...
Tom's of Maine toothpaste Botanically Bright.  Photo by BotanicalAccuracy.com.