Clades and Cladograms: Helpful Concepts to Understanding Phylogeny and the Hereditary Links Between Plant Groups

Cladistics is a system of classification…of course it is…that relates species to one another based on heredity and lines of inheritance.  Before you dismiss this as a totally boring topic, consider that these are tools, that with a little study, can go a long way in clearing up the murky waters of taxonomy and systematic botany.  Cladograms are a diagrammatic, graphic devices to visually display the relationships of closely related organisms, like the one below, and can be helpful to us in our efforts to understand the phylogeny and evolution of plants.  The ‘branches’ of a Cladogram represent clades, all of the descendants are of a chosen ‘root’ species.  Each clade must be monophyletic, complete, including all of the descendants of the root or ‘stem’ ancestor.  The APG demands precision.

“Cladogram (family tree) of a biological group, showing the last common ancestor of the composite tree, which is the vertical line ‘trunk’ (stem) at the bottom, with all descendant branches shown above. The blue and red subgroups (at left and right) are clades, or monophyletic (complete) groups; each shows its common ancestor ‘stem’ at the bottom of the subgroup ‘branch’. The green subgroup is not a clade; it is a paraphyletic group, which is incomplete here because it excludes the blue branch even though it is also descended from the common ancestor stem at the bottom of the green branch. The green subgroup together with the blue one forms a clade again.” (emphasis mine) This is from Wikipedia, generally a good source for an overview.

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In Pinnacles National Park on the High Peaks Trail

Brundage Mountain up out of McCall, Idaho.

Gardeners find inspiration and support from all over, from nature’s expansive landscapes to the very personal and intricate jewels of fellow gardeners, to botanic gardens and the nurseries that often fuel our ardor.  We visit gardens locally, and travel when we can, seeing and experiencing what other regions and countries offer.  Sometimes it is the human culture and its exuberance which seems to drive a place’s horticulture and gardens in directions and extremes different from ours, while our growing conditions are very close…in other gardens site conditions can be very different than our own pushing the palette far from that possible in our own.  By traveling we are ‘opened’, taken out of the familiar and our senses ‘sensitized’, as we take in the new and see the familiar in new ways.  Travel can make us more receptive.  After a Fall trip to New York, followed by one to McCall, Idaho, this Spring we visited parts of central and coastal California, later taking a couple weeks driving up across the Olympic Peninsula to Vancouver Island, peppering it with gardens new and familiar, adding another island, Salt Spring, on our return. 

Like our gardens, we gardeners ‘grow’ over time, learning and changing our practice, our experiences ever evolving.  Important to this process are those others we meet along the way who take the time to share their knowledge and experience with us, perhaps including plants or seeds, but more often simply their enthusiasm for what they do, and the sharing of their gardens.  This is important to us because the practice of gardening can be a ‘lonely’ art and the world of plants is far bigger and more complex than any one of us….If we are to do it well we must seek out the aid and friendship of others.  The emotional connection to what we do, creates a ‘tension’, that can be a source for the energy that drives us…and the addition of a little supplemental ‘fuel’ along the way can go a long way. Continue reading →

Edgeworthia chrysantha taken several years ago in Washington Park between the Rose Garden Store and the tennis courts.

[I know, many of us are already growing weary of the political circus/blood fest we now find ourselves in.  Since I’ve retired from the work day world, I find myself alternately blessed and cursed with time, time which I can spend working myself into some kind of fit, or wondering how did we get here, and, more importantly, how can we get out.  I know, this is not a horticultural posting, but I feel like if I’m going to ever garden happily again, if we are ever going to address society’s disassociation from the beating heart of this world, our lack of a healthy relationship with the life here on Earth, and begin to heal both ourselves and the landscape upon which our lives depend, we are going to have to change how we look at the world and each other, we are going to have to examine our values critically and sort out what is ‘true’ from what is expedient or simply common practice.  If life on this planet has any value we need to awaken to it, to listen and re-establish our relationship with it.  Part of this is in understanding the ‘truth’ that anchors all life, that binds us to one another.]

Recently, thanks to the likes of Kellyanne Conway and Sean Spicer, we have all been introduced to the concept of #alt-facts, or alternative facts, as if there can be two conflicting sets of fact that are somehow ‘true’ to those who proclaim them.  Facts, however, are ‘real’ and are rooted in the living/breathing world, they are part and parcel of it.  They are not beliefs or opinions that are subject to one’s personal position.  There is something universal and constant about them, otherwise, they aren’t facts.  They aren’t ‘true’.   Continue reading →

Trees originate in a particular environment, not an urban one. This landscape of California Oaks creates a beautiful natural alle’e through the woods. These native Oaks can soften a street scene over time, are well adapted to our street environment requiring little effort on our part beyond structural pruning.

The urban environment can be an extremely stressful one to live in.  This is no less true for plants than it is for us, the people, who created and maintains this place for our own use.  It is no less naive to believe that a tree, planted out by someone, no matter how much they may love at least the idea of trees, in a random parking strip or next to their place of business, will thrive after a year or two of well intentioned irrigation, on its own than it is to think that a child will grow up to be strong, happy and successful simply by having its first few years of nutrition provided for….Cities are economic and social constructs.  They did not rise ‘organically’ from the soil supporting a diverse and complex community of species.  Life has had to ‘fit’ in where ever it can.  Much has been unable to.  Many of us plant trees because we feel the loss, the absence of life, and realize that these places are less for it, that we ‘suffer’ because of this.  But we cannot simply add trees and stir.  These are ‘broken’ places and we have to pay more attention to our choices and provide better care than this place alone can provide…otherwise it would be like turning out our children, still unformed, on their own.  Even if we were Spartans and believed that only the ‘strong’ deserved to live, we would be dooming them in these modern, contrived and, in many ways, diminished cities.  As responsible parents and tree stewards, we are bound to them.  We owe them our best.  Without it they will fail and the world that we have built around us will be less as well. Continue reading →

This should grow big! 2′-3′ tall and 5’+ across. But not here. This one keeps coming back after some amount of the top growth rots back.

This is my Agave ‘Sharkskin’ before the onset of flowering

Acquired this on in Spring of ’14 a more compact form of the species with prominent white leaf markings.

Sharkskin bracketed by its parents, A. scabra left and A. victorian-reginae on the right

Hybridizing is always a bit of a crap shoot!  Cross two species and the progeny will range all across the morphological map!  Hybridizers grow on their seedlings and select those that share the characteristics that they’re looking for or individuals with startling and unusual features.  They toss the rest.  They in effect are giving their selections an advantage, an advantage they would never receive in nature on their own.  In nature hybrids can only occur when the natural ranges of the two parent species overlap and their proclivities align with the possibilities.  Plant breeders are not limited by this.  Pollen can be collected and stored from anywhere and used to pollinate selected plants.  In nature, survival is a numbers game.  Seedlings must be competitive in an existing plant community with limited available niches.  They have to possess a certain robustness.  Those that survive, grow on and perpetuate themselves, possessing survival characteristics that allow them to do so and have been blessed with the conditions that favor them.  Hybrid creations of nursery people and breeding programs may be lacking in these survival features.  They are pampered, lined out in nursery rows and flats. The result of their intentions may actually put their selections at a competitive disadvantage if they were to be left on their own in nature. Continue reading →

The Pruning Series, 4.  If you choose to read only one of my posts on pruning, this should be the one.

Pruning cannot save every tree. This large Magnolia appears to have lost its main trunk  long ago and is now surrounded by suckers and sprouts with most of the base rotted out. The section growing to the right is full of rot and is leaning over the adjacent house. It is common for trees like this, heavily damaged and in decline to sprout this way.  Sprouts such as these are weakly attached to the trunk and the structural integrity of this tree is very compromised.  I would not be surprised if spring’s new grew will be enough added weight to cause it to collapse on the house.  The entire ‘landscape’ suffers neglect.  I’m sure no one is monitoring it.  Such is the case with most urban trees.

Whatever your goals for pruning may be you must always keep plant health first and foremost in mind.  In many cases, especially with high value plants in our landscapes, this might be our only reason to prune.  In any good pruning class the instructor will emphasize in some form, the dictum, ’First, do no harm!’ which is often attributed to the medical world’s Hippocratic Oath.  It seems fitting to me to do this as both are dealing with life and promoting good health, only with horticulture and gardening our ‘patients’ are plants.  All organisms have a characteristic, genetically determined structure, that when compromised threatens its health.   All organisms experience stress and, if within limits, respond by strengthening their structure.  Expose them to excessive stress and physical damage occurs.  Storm damage, breakage, vandalism, branch failure following the growth of weak structure, a ‘burden’ of dead wood, diseased tissue, all add to the stresses on a plant and can all be relieved by good pruning…or exacerbated by poor or overly heavy pruning.  Timing can also be a factor as it can disrupt the natural growth cycle causing a delay in the plant’s acclimation to cold process. Continue reading →