Thursday, March 27, 2014

New logo for botanical detectives...

Botanical Accuracy has gotten a new custom-made logo designed by Clayton Leadbetter.  Love it! Thanks, Clayton!

Flowering ferns and other mythical greens

The Philadelphia Flower Show is a paradise for winter-weary gardeners.  It can also be great fodder for botanical accuracy blog posts, but I have to say that this year's show was a lot better than usual. It was a delight to be there in this seemingly perpetual winter.  As for botanical inaccuracies, there was only one that stared you in the face, label and all.
"Flowering Ferns", label seen at Philadelphia Flower Show.
Photo ©
This label is from a Dutch company's booth where they were briskly selling "Flowering ferns".  How can that be? Isn't that like unicorns or flying horses? A combination of features that has never evolved, in horses, or in ferns.

So what is wrong with flowering ferns, apart from the fact that they don't exist?  On the tree of life of plants, ferns (and horsetails) are located above the mosses and liverworts at the base, and below the conifers (spruces, pines, etc.) and flowering plants.  Conifers and flowering plans have seeds, but ferns, lycopods, and mosses have spores spread from sporangia, never seeds. Flowers and fruits only occur in angiosperms (flowering plants), a group that evolved a lot later than ferns. So what is in this bag for sale in this booth? A fern or a flowering plant?

"Flowering Ferns" packet, seen at Philadelphia Flower Show.
Photo ©
It turns out to be a flowering plant with fern-like leaves. The species is Incarvillea delavayi. It is in the family of Gesneriaceae, same as African violets.  Common names for this species are hardy gloxinia, incarvillea, Garden Gloxinia, and Delavays Trumpet Flower.  To add the inaccurate name 'flowering ferns', just add confusion. 

Wednesday, February 26, 2014

Pollen allergy? Not from thistles

This ad is marketing the allergy medicine Singulair (Merck) and it is titled 'go nose to nose with allergies'.  And right next to the nose is a very spiny, evil-looking thistle head with an abundance of red, small tubular flowers ready to release their pollen.

The problem is that people are mostly allergic to wind-pollinated plants that release dust clouds of dry pollen grains that fly through the air freely and land in our noses, eyes, and mouths.  The non-wind pollinated plants, such as thistles, get visited by insects that carry the pollen from flower to flower.  For the pollen to be a carried by insects, the pollen needs to be sticky so it stays on the animal.  And sticky pollen doesn't fly through the air freely and enters your nose as dust.  So, thistles are not common allergy plants at all.

The most common allergy-inducing plants are wind-pollinated grasses, some weeds (which is a group of a variety of unrelated species), and trees in the plant families containing oaks, birches, and other wind-pollinated trees.  But too often the insect-flowering plants that flower at the same time as the wind-pollinated allergens get the blame, as in this case.

I also think the Singulair marketers rather have a spiny evil-looking weed like the thistle in the ad, than a fragile grass with rather small, obscure flowers. But the use of the thistle spreads misinformation. People might start to pull up goldenrods, thistles, and clover because they think they cause pollen allergies, which is not true at all. If I was working at Merck, the producer of Singulair, I would be very embarrassed over this mistake.  

Tuesday, February 11, 2014

Are there cattails among the nymphs in the waterlilies?

Sometimes you run into botanical mistakes that just makes no sense.  Mistakes that are so strange, that you wonder not just want the author was thinking, but really, HOW did they get this wrong...  A reader of this blog (RO) sent me this example of such a preposterous mistake:

On Virginia Tech's online Weed Identification Guide, when you search for cattails, you find this:

Screenshot from Virginia Tech Weed Identification guide by
A nice page with a species description, but... the genus is wrong.  Cattail belongs to Typha (in the family Typhaceae, they have their own little family).  Here is a typical cattail in fruit:
Typha latifolia_10
A pair of cattail 'cigars' which contain the developing fruits.
Photo by Amadej Trnkoczy on Flickr, Creative Commons. 

Instead of Typha, the listed genus name is Nympha, which not only is a non-existent genus name, but probably was meant to be Nymphaea, the waterlily genus.  Sure, water lilies often grow very close to cattails in the edges of lakes or ditches, but they are completely different plants. Compare here:
waterlily banner
A great pair of Nymphaea, water lilies. Photo by Vilseskogen on Flickr, Creative Commons.

Nymphaea is of course named after the Greek nymphs, while Typha also comes from a greek word 'typhos', which is the ancient name for this plant.  Apparently cattails have long been associated with mythological creatures such as serpents and dragons.

The same information and mistake is showing up in University of Missouri's Weed ID iphone app, and they must have some kind of collaboration with the originators of Virginia Tech's Weed data.

My main issue here is that universities that put out online (or printed) botanical tools for the general public need to get at least the basic science correct.  People use these tools, which is great, but they will (and should) assume that the information is accurate, especially if if it is provided by a research and teaching university.

(Thanks to RO for sending me the link to the botanically inaccurate page.)

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
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 in Bloom
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

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

More teasels listed as 'thistle plant', this time on Colourbox (link).
Screenshot by
Dried flowering heads sold as 'dried thistle' by Country Creations (link).
Screenshot by

Saturday, January 25, 2014

Wanted: italics and correct capitalization

As a botanists and scientists I am sure most of us have pet peeves on how scientific information is handled in everyday life.  One of mine is the writing of scientific names for species, the simple Genus + Species epithet that is unique to every species and help us keep order among information and knowledge.  An example of a scientific name is Acer rubrum, red maple.

There really are very simple rules to follow in how to format these names, and none of these rules are really optional, especially not if you want to promote your company or work as scientific, correct, and professional. Here are the three simple rules:
  • Italizice species names
  • The Genus name is capitalized in the beginning.
  • The species epithet is never capitalized.
 The capitalization of the first letter of a Genus name shows that it is a genus.

For example: Acer, Rudbeckia, and Taraxacum.

The species epithet, the one-word addition  to the genus name that creates the species name, should never be capitalized.  In the past, sometimes words that originated from place names and people's names were capitalized, but that is no longer done. There is a great website called Curious Taxonomy that lists species named after all kinds of people, such as politicians, sports figures, actors, fictional and mythical characters, things and places around the world. 

Examples of correct formatting would be:
americanum, smithii, batesii, and yoda - after America, Smith, Bates, and Yoda. 

The italicization shows that they are scientific names, and not cultivar names or common names or other informal names. So for a cultivar of a species you would see names like this: Clematis alpina 'Ruby', where the cultivar name is not italicized and in quotes (read more here on cultivar names). To promote the understanding of the biodiversity of the world it is a great idea to have italicized names in concurrence with cultivars, common names and other information.  Italicized names are not harder to read, and they are unique, as opposed to common names, and can tell you a lot about the species.

Now, are these three rules followed outside the scientific world?  No, not all the time.  It is very common to see either no capitalization of genus names or capitalization of species epithets, and the lack of italicized species names are abundant. Here are some examples:
"Thuja Occidentalis" - at least the species name is in italics,
but occidentalis should have all been lower case letters. Homeopathic herbal medicine sold by TagAway.
(Note, it is homeopathic so it doesn't work, unless it is a placebo effect, link to more information.)

One of the worst offenders I have seen so far is LUSH, a company that creates wonderful soaps and other body products from natural ingredients.  Unfortunately their botanical science does not have the same quality.  They not only ignore all italicization of all scientific names in their online ingredient finder and in their catalogs, they also have started to capitalize some species epithets that never were capitalized even before (see 'Matricaria Chamomilla' and 'Pimenta Acris' below).  The other botanical and biological information on the LUSH website are also poor, but that will have to wait for other blog posts.
LUSH website showing 'Chamomile Blue Oil' with wrongly formatted scientific name. Screenshot by (cc) (link).
'Pimenta Acris' on the LUSH website, also wrongly formatted. This particular plant and website
has been featured on Botanical Accuracy earlier due to taxonomic confusion.
Screenshot by (cc) (link)
When it comes to labels in botanical gardens, it might have been hard in the past to make labels with italicized names, but that is changing with modern tools and machines.  Many public garden labels have scientific names non-italicized or in all CAPS, but I hope that is going to change with new labeling methods.
Plant label from University of Oxford's Botanical garden, showing all capitalized scientific name and no italics. 
© Oxford University, fair use. (link)
Companies and others that print their labels on paper for catalogs, seed packets, and directly printed labels have less of an excuse for not using italics.  Several seed companies get their formatting correct, for examples Renee's Garden (however, the scientific name that they list for feverfew is an older synonym, not the current name):

Seed packet label from Renee's Garden for Feverfew, Tanacetum parthenium (listed as Chrysanthemum parthenium).
(c) Renee's Garden, fair use (link)

Scientific names might seem intimidating, but they are very useful and can also be entertaining.  For more information and explanations, see this blog post by Benjamin Lord.

Sometimes you see family names italicized and that is not against any rules, but it is becoming less common. I never do it in my scientific writings unless a publisher for a particular journal or book insist on it, and in my experience this is mostly a custom in parts of Europe. It is not a common practice in North America.

Monday, January 20, 2014

Beware of the wronged coconuts

Coconut palms are the quintessential symbol of tropical paradise. Spindly, tall trees with large feathery leaves wisp in tropical breezes on tropical beaches of white sand, under blue sky and by turquoise water.

Beach in Hawaii with coconut palm tree.
(cc) anda (: on Flickr.

Up in the crown of the palm, a few coconuts are usually hanging, ready to fall down on you at any moment.  If they do, and they don't hit you, with some work you can get to the delicious inside of the coconut. (As a side note, when you consume the white parts inside, you eat or drink palm endosperm. In case you didn't know. )

This staple food plant is spread all over the tropics, and a well-known plant in many cultures, even urban cities of today far from tropical beaches.  It is a plant that is easy to identify, delicious, and quite symbolic for us.  Therefore, it is quite strange that in popular culture so many illustrators get this plant wrong.  Really wrong. OK, as an illustrator you can simplify a lot, that is fine, but that is not the same as changing the properties of a plant and create something that doesn't exist.

First, this is how a coconut plant looks like:

Coconut palm, Cocos nucifera (Arecaceae)
From Köhler's Medicinal-Pflanzen, public domain (Wikipedia)
  • Note the tall, skinny stem of even thickness, with horizontal leaf scars on it.
  • Note the big fruits (coconuts), aggregated close to the trunk at the top.
  • Note the leaves, in a rosette at the top
  • Note that each leaf is divided into tiny, tiny leaflets that are arranged like a feather along a midrib.  It it the midrib, the vein along the center, that holds together the leaf. Each leaf can be very long, up to 5 meters (15 feet) at least and all the little leaflets are loose from each other except at the midrib of the leaf.

Here is a closeup of a coconut leaf, showing many leaflets along a midrib:

Coconut leaves
Coconut leaf showing many leaflets connected along the midrib.
(cc) Azeem Azeez on Flickr.
So, how do some of  the clipart masters and popular illustrators show coconut palms?  

A quick Google search results in a variety of morphologies, most of them correct:
Screenshot of Google image search 'coconut palm clipart free',
 but a few hits that look like this:

"Palm Tree Clipart Image: Tropical Coconut Palm Tree Icon"
Image courtesy of
Coconut tree design
Screenshot from, a stockphoto website showing 'palm clip-art'.
(c), fair use.
Screenshot of, showing clipart with 'double coconut palm tree island and sun'.
(c) Hit Toon, fair use.

Do you see the problems here?  Hint - stems and leaves.

Coconut leaves are finely divided into small thin and long segments arranged along a midrib, like a feather.  But, these ones above have whole, undivided leaves, which sometimes are slightly lobed.  In fact, some of these leaves look more like banana leaves.

The stems should be evenly thick, and they should have horizontal, evenly distributed leaf scars towards the top of the tree trunk.  These have a variety of stem patterns and shapes.

One thing they get right, the placement of the coconuts.  But you wonder why are there nearly always three coconuts in a tree, don't you?

So, shouldn't illustrators have the freedom to simplify, improvise, and design their own plants?  Sure.  But if you use one of these examples, then realize that the adults and kids that see these images will think that this is how a coconut palm looks like, when in reality, that is not true.  So, even if these images are fine and pretty as clip art and design pieces, they are still very botanically inaccurate.
Screenshot of Google image search 'dog clipart free',
Illustrators often simplify drawings of dogs, elephants and chickens too, but the characteristic features are always there, trunk, wagging tail, 4 legs, beak and feathers,. and so on.  To change the features that are characteristics for the coconut palm changes the species, it changes what you want to illustrate into an imaginary plant. It is like drawing a dog with a beak - we would complain that it no longer was a dog.  Many people don't realize that these palm drawings are incorrect, because we have lost a lot of botanical knowledge in our societies.  We all still know how a dog looks like though!

Monday, January 13, 2014

Celery - stems, stalks, or sticks?

Celery is a vegetable and plant that is prominent in American cooking, and infuses both cooked and raw dishes with its very special flavor.  When I arrived in America I couldn't believe how much celery was added to tuna salads, soups, stews, and on plates with peanut butter.  Back in Sweden I don't think we ever had celery in our fridge, and I can't think of one Swedish traditional recipe that has celery in it.  So, it is a very common plant and food ingredient here in the US and many, many other cuisines, but it is not totally omnipresent.

You would think people might like to  know what part of the plant they eat, right? Well, that becomes a problem for celery.  Many, many times there is big confusion about what those crunchy green celery sticks (also called 'ribs') are.

 First, here is the species in question, a celery plant.

Celery plant (Apium graveolens, Apiaceae)
Illustration (public domain) from Thomé (1885), Flora von Deutschland, Österreich und der Schweiz (link)
And here, celery from a store.
Celery ribs from a supermarket.
(cc) Daniel James on Flickr (link)

And here, the celery 'stick', the part that we eat, cut up into small, crunchy pieces. 

Cut up celery sticks.
(cc) Dey on Flickr (link)
So, what part of the plant is this celery 'stick' really?  What are our options?  Well, plants have leaves, flowers, fruits, stems (branches, shoots, stalks), petiole (leaf stalk), pedicel (flower stalk), roots, tubers, and so on.  These are the botanical names we use for plant parts. All of these can be green, but mostly leaves, stalks, and stems are green.

On the internet you can find answers to everything. So, lets begin:

Yahoo Answers
"Both the stem and the leaves of a celery plant are eaten, but the long crunch part many people put peanut butter on is the stem" [this was voted the best answer on "Is celery a stem or leaves?"] 

Teacher's guide from New York Agriculture in the
"Celery we eat is the stem of the plant."

"Celery is used around the world as a vegetable for the crisp petiole (leaf stalk)."
"Is a celery stalk a stem?"
Answer: "yes so is rubarb"
"Is celery a stem?"
Answer: "No celery is a vegetable. Celery has a stem. A single celery plant has lots of stems actually. Most plants and trees have stems which are sometimes referred to as stalks."

Are you confused yet?  Here are some more variations:

GoodFood on BBC:
"A collection of long, thick, juicy stalks around a central, tender heart"

The Cook's Thesaurus lists celery as a 'Stalk Vegetable'. 

Seattle Times, Food & Wine section:
"By most definitions, a whole head of celery is a stalk and a single "stick" from the stalk is a rib. Some dictionaries use the accurate but clunky term "leafstalk" for a single rib."

Well, the confusion is total.  The 'celery rib' that we cut off the plant and chop up or put peanut butter on is, based on internet facts, a stem, stalk, leafstalk, and petiole, all at the same time.  This is not possible. It is one thing and one thing only.

Look at the plant.  At the top of your rib or stick are some leaves (unless you have cut them off, they were there before).  Only leaves.  There are no flowers, no growing part (with buds) that can lead to a stem that grows taller and taller, no fruits, no roots.  At the bottom of the rib is a white area and then a broadened base. You can easily break of a rib from the rest of the plant in your hand. 
Celery, as you buy it in the stores.
(cc) Popolon on Wikimedia (link)
Leaves are attached to stems and branches.  Where is the stem on the celery?  It is that small, disk-shaped woody part in the center of the plant.  The roots have been cut off, so you no longer see them.  But how does celery grow bigger and taller?  When the plant is old enough it will shoot up one stem in the center of the leaves, and that stem will then grow taller than the leaves around it, have smaller leaves on it, and eventually flower and set seed high above the leaves at the base. Look at the first picture on this blogpost to see a flowering celery.

The parts of a plant. Note stem, leaf, and petiole.
(c) Pearson Biocoach (link)

So, celery sticks and ribs are not stems.  They are part of the leaf, in fact, they are the leaf stalk, which is also called petiole. There are other ways to determine this too.  If you cut the celery rib across you can see many veins in it, and they are arranged as a U.  In most flowering plant stems, the veins are arranged in a circle, unless if it is a monocot, then the veins are arranged in a random scattered pattern.

So, when you eat celery you eat the bottom part of the leaf, a fleshy petiole. Even if it doesn't look like a leaf, it is part of the leaf.

One of the big problems here is that the word 'stalk' can be used for so many parts of a plant, including stem, leaf stalk, flower stalk, etc. No wonder people get confused.  In rhubarb you also eat the petioles (contrary to the answer on above). So who got it right in the quotes above?  Well, strictly speaking, only Wikipedia provided a completely correct answer.

What is maybe most dismaying is that there are many biology lesson plans out there where teachers are told to cut celery ribs and put them in water with food coloring to show how water moves through stems (example). (Some lesson plans get it right too, of course).  Sorry teachers, you are showing how water and nutrients are moving in a leaf, not in a stem.  And that makes a difference both to the plant and to scientific understanding among children and college students.

Sunday, January 12, 2014

Magilla Gorilla and shady cultivars

[This is a guest post provided by Dr. Arthur O. Tucker, Delaware State University]

I know that if you’ve gone to the garden centers in the past few years, you have to have spotted plants with the label of ‘Magilla Perilla’ and ‘Magilla Vanilla.’ American nurseries and 99.9% of web sites insist that this may be a coleus-like plant, but it is definitely a perilla, not a coleus. Both perilla and coleus are members of the mint family, the Lamiaceae.
'Magilla Perilla'
© Mississippi State University, fair use (link)
I e-mailed the company that introduced and distributed 'Magilla Perilla' in North America. Over a later telephone call, their “expert” insisted that these plants are perilla, not coleus, because the Japanese company that supplied them said so. Thus I was wrong and they were right.
Plant growing card for 'Perilla Magilla'. © Do Right', fair use (link)
Perilla, alias wild coleus or perilla, is a monotypic genus encompassing only one species, Perilla frutescens (L.) R.Br.   Perilla is a culinary herb commonly used in Asian cooking. This is an annual plant, even its tropical cultivar from Viet Nam, ‘Tia To’, only survives one growing season.

Perilla frutescens, the true perilla, as a red-leaved variety.
Photo (cc) by Henry Heatly (link)
After perilla flowers and sets seed, it dies like a true annual should; nothing you can do will keep it alive for more than one season. The other distinguishing character of the genus Perilla is that the stamen filaments are not united at the base (i.e., not connate).

Coleus is nowadays usually classified as the species Solenostemon scutellarioides (L.) Codd, with older synonyms being Plectranthus scutellarioides (L.) R.Br. and Coleus blumei Benth. Coleus is a tropical perennial that is often treated as a summer annual in northern gardens. The other distinguishing character of our garden coleus is that the stamen filaments are basally united (i.e., connate, not free as in Perilla).

A garden coleus, Solenostemon scutellarioides, one of many varieties and cultivars.
Photo (cc) brighterorange (link)
The trouble is that ‘Magilla Perilla’ rarely flowers. We finally obtained a flowering specimen (now vouchered at DOV herbarium at Delaware State University), and it has basally united stamen filaments, so it is clearly a coleus, not a perilla. It is also a perennial and, if taken into the greenhouse over winter, continues to grow and flower as a perennial, just like coleus. Thus, ‘Magilla Perilla’ is a regular coleus, not a special perilla
In writing The Encyclopedia of Herbs (Timber Press, 2009), I wrote: “And a word to the wise: ‘Magilla Perilla’ and ‘Magilla Vanilla’ are coleus… not perilla…." The editor changed this sentence to say that ‘Magilla Perilla’ is a perilla, not coleus, because, as she insisted, every web site said such, so I must be wrong. Of course, in my typical fashion, I went ballistic, so to calm me they changed it back to my original writing.  By the same line of thinking, is ‘Magilla Vanilla’ a species of vanilla, an orchid? Ridiculous!

This is a classic case of suppliers not knowing what plant species they are supplying, companies trusting the suppliers wholeheartedly without checking the provided materials, companies spreading the wrong information, and in the end creating total confusion.  The plant looks like a coleus because it is one. 

Despite this, public and private gardening resources call it a perilla or a 'hybrid' of Perilla frutescens, and it has even been given the fake scientific name 'Perilla magella'. Information like this is spread by sources such as agricultural extension services in several US states,  Royal Horticultural Society in the UK, Local Gardener, and Dave's Garden.  There are a lot of corrections of this mistake needed online, in stores, and in print.  Mistakes happen, but when known, they should be fixed as soon as possible. 

So, to conclude:
'Magilla Perilla' and 'Magilla Vanilla' are the same species as the commonly grown coleus, just different cultivars. Their scientific name is Solenostemon scutellarioides. Neither of these two plants have anyhing to do with the culinary herb perilla.

A correction of this botanical mistake was also published in the Newsletter from the Herb Society of America in 2010. [link]

Friday, January 10, 2014

Frosty fern? It is a variegated spike moss

Before Christmas a fern-looking plant often shows up in the supermarkets and is marketed as 'frosty fern',  a name it gets from its fern-like leaves (more on that later) and white-tipped branches.

'Frosty fern' for sale, with rather zoologically inaccurate cardinals as highlights, but that is for another blog.
Photo (cc)

Frosty fern for sale at Shoprite in New Jersey, USA.
Photo (cc)

But, in fact, it is no fern at all.  It is a Selaginella, a spike moss in the lycopod group.  It is also called African club moss or Krauss' spike moss, and its scientific species name is Selaginella kraussiana (family Selaginellaceae).  Many club mosses belong to another lycopod family, the Lycopodiaceae.

Ferns below to a different branch on the green tree of life, they are not lycopods.  The two evolutionary branches are about as different as a turtle and a salamander. We easily keep salamanders (and other amphibians) apart from turtles and tortoises in our brains, but green things from many different branches on the tree of life look very similar to us.

Lycopods evolved before ferns and have spores, just like ferns, but lycopods differ a lot in how their leaves are constructed.  Look closely, and you can see that lycopods have branches and stems with tiny scale-like leaves.  These leaves are called lycophylls. 

Some people mix up this plant with mosses, but real mosses are smaller and do not have roots like lycopods do.  Mosses also have scale-like leaves, called microphylls, and they are very similar to lycophylls just smaller.  So club mosses and spike mosses are not mosses.
A branch of a Selaginella (Frosty Fern) showing many, many small scale-like leaves.
Photo (cc)
Ferns on the other hand have large leaves, often divided, and these leaves are called euphylls, which means 'true leaves'.  Other groups with true leaves are conifers (needles!) and all flowering plants (oaks, grasses, and dandelions and such).  True leaves have many veins in them (look closely), but lycophylls and microphylls have only one vein in each leaf.

So, the common name of this plant is often 'frosty fern', and it is not uncommon for common names to give the wrong impression of a plant's taxonomic belonging.  Just think of names such as 'lucky bamboo' (not a bamboo at all) and reindeer moss (a lichen).  Common names are everyday names, often traditional, used among people so we can communicate about the plants around us.  The real problem starts when we think this plant is a fern.  And that happens, and then the botanical mistake is a fact induced by the not-so-great common name.  Such as in this example:
"Never allow the soil to dry around your frosty fern. This fern doesn't tolerate dry periods or waterlogged soil."  (link to source at
Suddenly the spike moss became a fern for real in that quote. And suddenly, a botanical inaccuracy have been introduced in our way of thinking about this plant, because of its name. So therefore it is best to avoid such common names and instead use names that are more appropriate, like Krauss' spike moss.  

The same thing can happen among animals, but usually we know that guinea pigs are not pigs, and that seahorses are not horses, and that ant lions are only very, very distantly related to lions. All because animals are a little more charismatic than plants and it is easier for us to relate to them as pets, food, dangers, or just crazy, cool species. (In reality plants are more of your food than animals are and as dangerous and cool as animals.)

Here is a great blogpost about this plant and its botanical inaccuracies from New Hampshire Garden Solutions.  George Rogers has also written about this plant in a great little article in North County Current. Just remember not to introduce this non-native plant to your subtropical garden in southern United States, since it can easily become invasive.