IMPOSSIBLE FAMILY TREES
Taxonomists are generally wasting their time in trying to categorise the living world into family trees. It used to be thought that plants diverged by natural selection (including random gene mutation) into an orderly family tree that could be drawn just like a family tree of descendants of human lineage. It is now known that this is not true, and that genes have been spreading horizontally across all six (or seven) known kingdoms (animal, plant, fungi, protista, archaea and eubacteria (and prokaryota), but there are probably even more) by various mechanisms including viruses, plasmids, bacteria, and even by things yet to be discovered. There has been, and is still on-going, lateral gene transfer between species and kingdoms such as to make drawing a family tree impossible. Biologist are now also finding that even genes and other bits of RNA and DNA do not code for everything, and that environmental methylation and other epigenetic processes are also very large players in the differentiation of species. Even Lamarckism may be at work in some cases. Heredity and evolution is hugely complex. The more is discovered, the more complex it becomes. See Epigenetics.
Even as we speak, geneticists are busy mapping genes from plants and then deciding that a plant which was once thought to belong to a certain family, actually belongs to a different family. What they fail to realise is that it may, in fact, belong to several dozen families (and not all drawn from the plant kingdom), all at once, but from different eras. All taxonomic categorisations are doomed to failure. It is not possible to draw a fractal family tree, nor to say which plant belongs to which family.
Nevertheless, taxonomists persist in their current pastime for they have, at present, no other method of displaying (some) relationships between members. The author will endeavour to keep up with the constant changes they make as to which plants they think belong to which families; but in all honesty, they really do need to move on and realise that each plant is unique and un-categorisable. The master plan for every flower is drawn from a variety of sources, which could include animals, virii, bacteria and even free-roaming RNA. And they are still evolving. Hybrids abound from which new varieties may eventually emerge. The divergence of species. It is little wonder that biologist still argue over whether there are only five, or are six, or are as many as seven known kingdoms. And that is not counting the unknown unknown ones.
Cell design, for instance, reflects a haphazard historical legacy of happenstance structures drawn from a plethora of mal-adjusted random sources and constructed blindly without aim or purpose to produce a workable solution (one whose only aim is to self-replicate) to hundreds of ephemeral and ever-changing problems. The cell is not perfectly engineered; it has faults which it either lives with or gets around; or finally succumbs to some external threat. That this is so can be gleaned from the fact that there is not just one type of cell, but millions of different cells. All doing different things. The only thing they have in common is that they are living (they self-replicate, and reverse the normal direction of entropy: utilising energy to produce all sorts of chemicals).
A single-cell organism is more like a computer based on chemistry. It is running a chemical program which responds to environmental changes by the use of chemistry. Stimulate or provoke it in some way, and the cell responds by making more of a chemical that produces a plethora of other chemicals that serve to mobilise the cell and move out of danger or to counter the change in circumstances. It is full of response and feedback mechanisms, so many that biologists are only now just scratching the surface of exactly how a single cell actually works or responds to stimuli.
Multi-cellular organisms, like plants, insects and animals, are many times more complex. In a multi-cellular organism, each different type of cell has lost (or possibly never had) the ability to live and reproduce alone, and each now relies on the correct co-operative response of differing neighbouring cells in the multi-cellular organism to live, survive, respond to environmental change or stress, and reproduce. In any one plant there are possibly hundreds of differing cell-types. Each plant may have some cell-types in common with other plants, but possibly not all cell-types. Some plants may have unique cell-types. It is probable that cell-types are shared between some species and not others, but those that do not have them may possibly gain them at a later stage, or possibly lose that cell-type altogether. This constant swapping, sharing and losing of cell-types has been going on for millennia (through the action of genes). Each different plant may be a chimera between certain other plants. This mish-mash between thousands of differing plants (leaving aside for the moment that between kingdoms) is almost impossible to sort out taxonomically. It is just not possible to say that plant 'a' belongs to family '1'; when it actually belongs to a great many different families all at the same time. In fact, the 'family' has also been changing over time and does not remain constant, set in stone forever like taxonomists would like us to believe. All living organisms are in a state of everlasting flux.
Classifying any organism into families (or family trees) is an impossible task similar to trying to draw the connections between strands of spaghetti in a bowl. And doing that whilst someone else is stirring it, another is eating it and a third is slowly adding more spaghetti to the bowl.
Classifying the living world is not, and never will be, like classifying atoms into the Periodic Table nor nuclides into the Segre Chart. The living world is a holistic whole; no one species can be taken in isolation.