Why are Mushrooms Not in the Plantfiles?By Geoff Stein (palmbob)
December 12, 2011
Ever since I have been a member of Davesgarden it has always concerned me that we did not include fungi in the plantfiles. There is a forum for fungi. I see a lot of fungi growing in my garden. I see fungi included along with the other plants in another major garden web site. I would like to learn more about fungi and this is my favorite site to learn about things like that. So why do we leave them out, those pesky fungi? Too many of them? Too hard to identify? Too much trouble? Well, it turns out, to my surprise, that fungi are simply not plants. Oops.
Typical mushrooms found in my garden... sure look like plants to me, save maybe the lack of chlorophyl (turns out that's an important lack)
So the Astrophytum cactus on the left, though weird looking, is 100% plant, while the plant-like mushroom (Deadly Aminita) on the right is NOT a plant... (right photo Wikipedia)
As I did in a previous article, I have to mention my failing at recalling much of my botanical education in college. Though most of it does not stick with me today, I was certain that we covered things like mushrooms in that class. Were mushrooms plants back then, and now they are no longer? Did they get demoted? Promoted? What happened to them? They sure look like plants to me. They have roots, they grow from spore (like ferns do), they live in the garden and my dogs eat them (like they do my other toxic, as well as non-toxic plants). They don't run around like animals. They are not microscopic like bacteria or viruses... oh, well, I guess some fungi are microscopic. But still, how could these things not be plants? If I recall, Mycology (the study of fungi) was always included in Botany in school. But I guess things change the more we learn about them.
I find these growing everywhere. They are mushrooms my dogs like to eat, fortunately non-toxic... (in between the mushroom-like artwork)
The Asplenium (Bird's Nest Fern) on the left is showing its underside loaded with spore. This is a plant; the right photo (from Wikipedia) is a mushroom showing its spore surface... but it is NOT a plant
What is a plant? Plants are forms of life that have most of the following properties in common: photosynthesis and the ability to create their own food; rigid cells containing cellulose, aside from the presence of a cell membrane; storage of energy in the form of starches and/or sugars; eukaryotic cells (cells with nuclei and cell membranes); are generally (but not always) multicellular; have growth that is continuous at their meristems (when they have meristems); do NOT have sensory organs or nervous systems; do not have specific methods for mobility; have both haploid and diploid life cycles (sporophytes and gametes). Wow. That seems like a pretty complex definition for what most people can just tell by looking what a plant is and what a non-plant is. But as it turns out, it's not so clear. Algae can be plants... or not, for example. Some algae (green algae for example) are considered plants, as they fill most of the above requirements. But other forms of algae, like red, yellow-green etc. do not and have a Kingdom of life all to their own (I am pretty sure this kingdom did not exist when I was in high school).
Red algae (left) and a seaweed species (right), though plant-like are not considered plants, either, or at least are not included in the same kingdom as the plants (photos Wikipedia).
And fungi, as it turns out, do NOT fit most of the above definitions of plants, despite their looking a lot like them in some cases. There are LOTs of fungi, however, that do NOT necessarily look like plants. I tend to think of mushrooms, and sometimes mold, when I think of fungus. But there are all sorts of fungus that do not look like either of those. Even mold is a bit of weird organism to be necessarily considered a plant. But life forms like ‘ring worm' and athlete's foot (dermatophytic fungi) are somewhat unplant-like creatures I deal with in my line of work. There are also single-celled organisms, like yeast and other pathogenic fungi that are very unplant-like as well that I also have to battle in the veterinary world. And of course there are many other forms of fungus I am completely unfamiliar with that are most definitely very unplant like.
These Asian mushrooms are all edible and are usually what I think of when I think of mushrooms. Photo from Wikipedia
More typical mushrooms: Portabellow (left) and Psyllicybin (magic type) right- photos Wikipedia
Perhaps less typical mushrooms, but still somewhat plant-like fungi (photos from Wikipedia)
less typical fungi that seem much less plant like: budding yeast like that found in making bread rise (left), and Candida yeast that can infect your mouth (photos Wikipedia)
Molds (the kind you make blue cheese with- left), and the Penicillin molds like that growing on the orange (right)- photos Wikipedia
Athletes foot fungus (left) and another skin fungus sometimes referred to as 'ringworm' since if forms a ring-shaped lesion (right)- photos Wikipedia
Cryptococcus neoformans, a very nasty and often difficult to treat fungus that can end up in us and our pets (photo Wikipedia)
Aspergilla- a common mold found everywhere, but this one is in someone's lung. Does not look or act like a plant there. Photo Wikipedia
Fungi, as it turns out, just like the members of the Algae world that did not make the cut when it came to deciding what was a plant and what wasn't, got awarded their own kingdom as well. Most forms of Algae, including many seaweed, are also not in the 'plant world' thanks to today's classification. This is also why lichens are not found in the plantfiles either (these a fungi with symbiotes making their classification tricky, too). With today's ability to do DNA testing and evolutionary biology, one can get a clearer (or murkier, depending on your point of view) idea of how all forms of life are related and who is more closely related to who. As it turns out, fungi are genetically more closely related to animals than to plants- WHAT!!??
This sea of palm grass (left) on land are considered representatives of the plant world, but if similar life is found growing in the sea, like this kelp (right), turns out it's not a plant (left photo Wikipedia)
Lichen are fungi... and not. But they are certainly not included in the plant world- photo Wikipedia
Fungi have chitin in their cell walls (a trait only shared by some animals- not plants). On the other hand, fungi have no cellulose in their cell walls (which all plants have). Fungi do not make their own food, but rely on other food sources (like animals do, too). This is why fungi are called Saprophytes (live off other's dead or dying tissues, sort of like maggots do). Some fungi have motile flagella which is definitely not a plant characteristic, but is shared with some animals along with a few other oddball life forms that don't fit in the plant, animal or fungal kingdoms (yikes, how many kingdoms are there?). Though seemingly a picky point, fungi produce lysine in a chemical pathway similar to what bacteria use (unlike both plants and animals). I guess this also means bacteria are not in the animal kingdom (where have I been?). Also, many fungi have hyphae which are cells that have multiple nuclei, and tend to grow by just stretching, maintaining the same cell walls, while similar plant-like organisms would be going through cell division to create similar structures (this trait is shared with some oddball pathogenic life forms called Oomycetes, which include many things that make plants rot... but are not included in the fungi, either). So many new classifications since I took Botany! Seems like I must have taken that class in the dark ages.
This fungal collage is in Wikiepedia on the site concerning fungi, and is a wonderful shot of various and very differnt looking fungi, from mushrooms (upper left) the the bread mold (lower right)
But if you are confused about what is related to what, be comforted that you are not alone. In fact, as of this last year, the whole Kingdom of life classification system has been in question and few experts can agree on its replacement. And there are even questions about what is life. Where do viruses fit in? What about prions (those pesky bits of genetic material that cause diseases like Mad Cow). Aren't these forms of life... or not? The more we know, the less we really know. Personally I liked it back when things were animal, vegetable and mineral. That seemed simple enough. That was back when the Greeks ruled the world, though. Guess it's time to modernize and just be happy with that new fact that plants and fungi are not as closely related as we once thought.
So back to mushrooms, which are obviously still ‘plants' to me. If Davesgarden agreed to include mushrooms in the plantfiles, it could become a slippery slope and they would then have to consider including other members of the kingdom Fungi as well. And before you know it, all forms of life would be in the plantfiles. I have suggested since we also have insects and birds on Davesgarden, there could be a section for fungi that would be totally separate, but it just sounds like too complicated a door to open, perhaps. Just know it is not because the Davesgarden administration has any prejudices against mushrooms that they are not included in the plantfiles. It's just they are not plants....
I thank Wikipedia for the use of all the photos in this article this month. One should really help Wikipedia stay in business and donate if possible.