I’ve made no secret of my skepticism about the dandelion microspecies; but like a good scientist, I am willing to consider the evidence. On the observations page for Section Taraxacum, there are 126,751 observations. By far the majority are identified as Taraxacum officinale (strangely, the Taxonomy tab for Section Taraxacum says that there are 131,233 observations of T. officinale, which raises some questions). Nevertheless, the same observations page also says that 91 species have been observed. Therefore, I scrolled through the list of species on the Taxonomy tab, and opened each taxon page that had >0 observations. I went through one by one, looking at bracts, leaves, stems, whatever I could think of that might differ between species.
I’m not seeing it. Okay, there are differences in the degree of red pigment in the stem and midribs – there are many, many plant taxa in which that trait varies among individuals and/or under the influence of the degree of sunlight. Okay, some species have floccose hairs, others do not; but that would only result in two species if it is considered an important trait. Okay, there are degrees of leaf lobing – from broad leaves with shallow serrations as in Taraxacum sundbergii, to triangular teeth touching the midrib as in Taraxacum acroglossum, to lobes with long, narrow tips as in Taraxacum eudontum, or even nealy linear as in Taraxacum incisum; but by far the majority are basically the triangle-tooth type. I noticed that some have opposite lobes like Taraxacum acuitifrons, whereas others have alternate lobes such as Taraxacum alatum; I suppose that could be important, but even ading it to the other traits I mentioned, we still don’t have enough dichotomous choices to key out all of the microspecies.
The names are not very helpful, as they suggest more distinctness than is visible. “Reflexed-bracted” – many of the species have reflexed bracts. “Orange-flowered” – the flowers are a slighly more orangey shade of yellow than some others, but not so’s you’d notice unless you had another kind right beside it.
In the end, I only found these few which stood out to me as distinct enough that I would feel confident about identifying them:
- Taraxacum sinuatum because the teeth are distincly wavy-edged like the blade of a kris
- Taraxacum pectinatiforme because the leaves are almost bipinnately lobed
- Taraxacum cyanolepis because… those bracts
- Possibly Taraxacum baeckiiforme, if those very short flowering stems are a consistent trait
- Taraxacum lidianum because it doesn’t really even look like a Taraxacum; I would have thought it was more like Hypochaeris, and wondered why the flowering stem did not branch
All the rest, I would have put the glabrous or mostly-glabrous ones with few bracts as within the expected range of variation of T. officinale and been confused what to do about the heavily floccose ones and the ones with many bracts.
The reason why this is in General and not in Nature Talk is because I am trying to understand what is visible in those observations that allowed them to be identified as those species. Since very few of them are Research Grade, presumably the observers who know enough about dandelions to upload them as those species would appreciate having someone else who can second their identifications. Also, I get the impression that dandelion aficionadoes consider that many of the “Taraxacum officinale” are misidentified, and it seems likely that at least a few of those six-figures of observations show the right characteristics to be corrected.
For my educational edification, I went ahead and uploaded my own dandelion observation – my first and so far only. I didn’t take 5, 8, or 11 pictures like the observers of most of the other species; but I did take three.
Fist, the overall plant habit:
Next, the backside of the flower head, since I know that bracts can be important:
And finally, a detail of the leaf:
(I have heard mention of the “first” leaf of the season; but most places I have lived, dandelions are evergreen, and it is hard to say when the season begins or which leaf is therefore the first.) Here is the link to the original observation.
So: based on these three images, do any specific species or microspecies come to mind? What is missing for you to rule out others? What are the minimum parts to photograph for an identifiable observation? To me, it just looks like officinale, like most of the putative species I looked at, but I am open to being persuaded.