The Science of Botanical Art


By Dick Rauh  

Originally appeared in The Botanical Artist, Number 25


Flowers are great. They just go their own ways adapting to new climactic conditions, adapting to new pollinators, developing new scents and colors and times of ripening and devices for seed dispersal, and for the most part couldn.t care less about how we feel about them, with the possible exception of some adaptations made to capitalize on man.s existence suggested by Michael Pollan in his Botany of Desire. We humans, on the other hand, can hardly keep our hands, or minds off the plant kingdom. The need to understand, name, classify, systematize, categorize, draw, photograph, and somehow organize, and thus exert some manner of control over them seems built into our character. As long as the plants don.t suffer, we might as well make the most of it, because, as artists, recognizing similarities and differences in the things we see, is our stock in trade. The groupings, large and small, help us to identify salient features, and ultimately, the more secure we are knowing what category we humans have placed a particular plant, the more securely we can make a more accurate and believable rendering. 

Unfortunately the higher up on the classification scale one gets from the plant in hand, the more likely there is to be disagreement among the .experts. as to how to group them. As I may have said before the science of Botany, or Plant Sciences (as it now more commonly referred) is constantly evolving itself, and even its name subject to change. 

When I was a boy things were simpler. There were two kingdoms, animal and vegetable. I remember playing a game where things were categorized into animal, vegetable and mineral, but we no longer have the luxury of so simple an answer. Its interesting that the flyleaf of Morphology of Plants and Fungi by Bold, Alexopoulos and Delevoryas written in 1987 gives a comparison of some botanists classifications, and shows a shifting that continues today. There actually exists an organization known as the Botanical Congress that meets every six years, and passes judgments on such topics as this. 

Roughly the two kingdoms of Animalia and Plantae were broken down into five with the addition of Monera (the one-celled bacteria), Protista (which included the one-celled eukaryotes and the algae) and Fungi. The recent meeting of the Congress in St. Louis shifted even this. They recognize three .superkingdoms .; .bacteria . which includes the one celled prokaryotes (cells that are the most primitive of all that have no organized nuclei or enclosed breathing or energy producing apparatus), Archaea, another group of simple one-celled organisms that have particular adaptations to extreme conditions, but are sufficiently different from bacteria to rate their own superkingdom, and Eukarya, the building block of all more sophisticated living things, with an organized nucleus, mitochondria, plastids and other developed inner bodies called organelles. 

With the growing refinement of classification due to increasing knowledge of molecular make-up, the science of systematics is more objectively grouping organisms, and characters invisible to the eye and even the most penetrating microscopes are revealing similarities and differences that are making for some interesting if unexpected bedfellows. The one .kingdom. that has proven the most objectionable .Protista. has been abandoned, and the algae, which were its largest group, have been broken up, largely because of the type of apparatus employed in the process of photosynthesis. The suggested new .kingdoms. are Animalia, Fungi (interestingly the scientists have discovered that fungi are closer to animals than plants), Red Plants (red algae), tramenopiles (a recently discovered group that looks like plants but does not perform photosynthesis. Brown algae and diatoms are also included here) and the larger kingdom Green Plants which now includes the green algae along with all the others originally included in .Plantae.. To review, the current thinking is five kingdoms - Animalia, Fungi, Red Plants, Stramenopiles and Green Plants. 

Now that we have isolated the kingdom problem (at least for the moment) we have only just begun creating a hierarchy to confuse and befuddle students of the biological sciences. Using Liriodendron tulipifera (Tulip Tree) as an example, let me run down the increasingly specific categories. First under kingdom in the plant sciences is division, and like most of the higher groupings there is a suffix (in this case .phyta.) which comes with the classification. Flowering Plants (which includes Tulip Tree) are in the division Anthophyta. A synonym for this is Magnoliophyta. Both are acceptable. The term Angiosperm which means the same thing is becoming less accepted (thanks to the Botanical Congress) but since such terms die hard I.m sure no one is liable to ostracize you if the name slips out. So here is the .highest category. into which our Liriodendron fits. Next below division is .class.( ending .opsida.), and in the Anthophyta there are only two. Magnoliopsida includes all the dicots, and Liliopsida the monocots (if I.m talking over your heads here for the moment be patient- a future article will attempt to clear this up). Liriodendron is a dicot, guess what class. Conquist, a leading American taxonomist of the 20th century stresses the next classification the .subclass., and I tend to go along. got to follow some leader, or the going here gets as slippery as a banana peel. I do have to warn you however that this is not universally accepted. When it gets to these in-between groupings there are many who espouse the concept of .super-order. instead of sub-class, but after confused you completely, lets go back to subclass. Conquist groups the Magnoliopsida into 6, from the most primitive, Magnoliidae (where our hero belongs), to the most derived, Asteridae. As you may have guessed the telling suffix here is .idae.. 

The next categories are more obviously dependent on similarity of characters. They are .order. with an ending of .ales., Magnoliales in our case, and .family. with a suffix of .aceae. hence Magnoliaceae. As artists this heading tends to be the most important, because we can use it to stress those features in a particular plant that tie it to its nearest relatives. Certain families have very obvious commonalties, the striking reproductive organs of the Malvaceae (the Mallows) for example where the filaments form a sleeve around the style, ending in a cluster of anthers below a multiple armed stigma, the extremely zygomorphic flowers of Orchidaceae, the bilabiate, lip-shaped flowers of the Mints, with their square stems and opposite decussate leaves, the composite inflorescences of the Aster. I could go on and on- but you get the idea. 

Below the .family. category we come to the two that, as of the moment, identify the particular plant throughout the world with the two defining words conceived by Linnaeus in the middle of the 18th century, the Latin Binomial. I say at the moment, because I understand there is a movement in the Botanical Congress to shift the nomenclature to one more closely tied to the new science of cladistics which stresses molecular data, and the use of computers, and would substitute .clade. for .family. and numbers for the Latin binomial. We will see. 

The first part of the binomial is the category, genus., and here for the first time we abandon any defining suffix. Liriodendron is the genus name. Next in this twosome is the specific epithet, or the species, the term that identifies the ultimate reproducing unit, this plant and no other. This is a term that can describe some feature of the flower or plant- in this case tulipifera or tulip-shaped, or color purpurea (purple), or location, canadensis, or person. There are rules here that are universally applied. 

In print the binomial is italicized, the first letter of the genus is capitalized and the rest in lowercase (even when the specific epithet is a proper name). When we write a Latin Binomial, or calligraph it on our paintings it is accepted that we underline the phrase, instead of italicizing. Even though the species is technically the lowest breeding unit on the scale, there are some categories that come below - races, cultivars, variants, hybrids, usually which stress size or color or some adaptation of the plant to habitat that isn.t sufficiently different to warrant a new species category. 

So to review, our Tulip Tree is in the Kingdom Green Plants, the division Magnoliophyta, the class Magnoliopsida, the subclass Magnoliidae, the order Magnoliales, the family Magnoliaceae, the genus Liriodendron, and the species tulipifera. Whew!!!