Botany Without Borders

Botany transcends the borders of time and space. Past and present are welded together in the body of the plant and distance, certainly national borders, is hardly an issue in plant biology. Modern plant form, the most obvious feature of plants we see all around us, goes back hundreds of millions of years. We detect evidence of ancient morphological features in every plant we observe, and we can infer evolutionary change in a host of plant features. Luckily, plants are there for us to observe on the cheap, without specialized laboratories, costly expeditions, or elaborate tools. Perhaps more than any other organism, plants tell a story of their long evolutionary history in their shape. Their frank physical form-- roots, shoots, leaves, flowers, and seeds, tells us about how plants have adapted to their surroundings over millions of years of evolution. By observing plant features we can look deep into the past of the species. Their structural adaptations are written, or more accurately, sculpted all over them, for example in the shape of leaves and flowers, in the modular growth form that every plant possesses, and in the many ways that plants maximize photosynthesis while minimizing water loss. And those are just macroscopic features. Even the molecular evolution of plants is apparent just by using our noses. The way a lilac smells, the flammable essential oils of an orange peel, or the acrid odor of the tree of heaven, Ailanthus altissima, all provide insights into plant evolution. You don't need to be a scientist to cross the border between plants and humans, because so much of their evolutionary history is there to observe.

The bottom line of plant evolution is that plants have learned to cope with a hostile environment since they first moved onto land. They are especially adept at preserving resources such as nutrients and water. There are two main reasons for this. First, plants are rooted in place. Their roots can spread toward nutrients or they may become symbiotically involved with fungi or bacteria to enhance their nutrients, but plants cannot get up and search for a more favorable spot. Second, plants lose water as they perform photosynthesis. As we'll discuss in detail below, the photosynthetic process involves a constant exchange of precious water vapor for abundant carbon dioxide, which plants use to produce carbohydrates. To cope with the constant threat of dehydration plants have devised thousands of strategies for conserving water, some of which we'll study in these pages. As experts at adaptation, plants offer us valuable lessons about how to cope and thrive in our surroundings, how to build better buildings, plant better green spaces, and how to insulate ourselves from excessive cold and heat. Many of these solutions are quite simple, just waiting to be adapted by designers. So whether we consider the succulent leaves of a beach plant, the prickles of a cactus, or the climbing habit of a jungle vine, the basics of plant form open a useful window on plant evolution.

Most of the plant form on these pages reflects growth patterns of seed plants, angiosperms (plants with flowers) or gymnosperms (plants like pine trees). These plants are the most common and therefore familiar, but seedless plants such as ferns have much to offer as well. It is interesting to note that certain growth patterns of fern forebears can be detected in modern plants, and these are well worth studying. For example, traces of the way fern fronds unfold, the wonderfully linear display of spore cases on the undersides of fronds, and the free expression of hairy surface growth, are all features that can be observed in modern land plants. Ferns are pretty as well. Their delicate beauty, gently unfolding above the fallen leaves of last autumn, belies an era when ferns were the dominant land plant, producing forests of towering trees.

Spore-bearing ferns and their allies are wonderful in their own right. They carry rich information about the evolution of plant form over millions of years, but seeds, which we will examine throughout these pages, are in many respects the signal example of plant evolution. Their role as dispersers, protectors, and nutrient providers are the key to understanding the overwhelming success of plants on Earth. Seeds with their many adaptations to life on land help us understand why plants are so widespread in the terrestrial environment. Because seeds are so well built for dispersal and so efficient in the other jobs they do, such as storing and mobilizing nutrients for the developing pre-photosynthetic embryo, they have helped plants colonize all parts of the planet. Plants transcend physical borders thanks largely to seeds, a radical evolutionary innovation.

It's no surprise that seeds inspired one of the most important design innovations of the 20th century, Velcro. A quick internet search will tell you that Velcro was invented by George de Mestral, a Swiss engineer who garnered his inspiration from the prickles of a humble burdock seed. De Mestral understood the potential of the burdock seed capsule when he saw how stubbornly the seeds fastened to his dog's coat. He set himself to designing a man-made product that would mimic the retrorse prickles of the burdock seed coat, which proved so effective in dispersing themselves, compliments of his dog. Good observation and hard work paid off. Though not well accepted at first, and in spite of its humble beginnings mimicking a pesty weed, Velcro is ubiquitous today. It is supported by hundreds of patents and is part of the design of innumerable products. The international manufacture and sales of Velcro and its applications represent a multi-million dollar industry. Velcro is used around the world in every conceivable way, and in one way or another, it is part of everyone’s life. Like the burdock seed, Velcro has dispersed all over the globe. Similar to plants, Velcro transcends borders, not just the borders between countries, but the insidious, generally impermeable border that separates humans from the plant world. Given that we can use plants as the basis for potent decorative, physical, and utilitarian design, perhaps we should take a closer look at the basis of their evolutionary power.

Looking at a Plant

Southeast of London in the distant suburb of Down stands Downe House, the curiously named home of Charles Darwin. Standing In the garden at Downe House, I learned that Darwin used to stoop and look at a flower for minutes on end, ten, fifteen minutes of rapt contemplation. The discovery of this anecdote was vindication for me. In crowded Cambridge, Massachusetts, my postage stamp garden with its sixty-odd plant families lies in the middle of a “village” of several family dwellings. Every time I study my plants someone is watching me, and since I don’t smoke or own a dog or water a lawn this makes me a little weird in the context of our neighbors. Standing in Darwin’s plant-loving shoes, or pretending to do so, somehow makes things a little easier.

Darwinian evolution (and all science) is based on a singular unifying principle: The Naturalistic Philosophy. Simply put, the Naturalistic Philosophy assumes that natural phenomena have natural causes. We can come to understand those causes through asking the right questions and studying nature in an appropriate manner. By “appropriate” I mean that we use our observations of nature as evidence for answering the questions we pose. This proviso simply means that nature is explained by nature, not by religious texts or belief systems. Corollary to the Naturalistic Philosophy is the Mechanistic Theory, which states that living (biological) systems are constrained by physical and chemical conditions. Water, light, nutrients, and temperature are some of the conditions that influence plants, and we’ll address all of them on these pages.

But these pages are for designers, not scientists. When we look at plants, is it impossible to gain understanding without considering the Naturalistic Philosophy and the Mechanistic Theory? Do we have to reduce the plant to an evolutionary machine that eats, breathes, and reproduces? Of course, the answer is no, no more than we reduce humans to their separate parts, their functioning cells, or their molecular components. Plants are perhaps foremost things of great aesthetic beauty. Symmetry and asymmetry, modular growth patterns, rhythms of opening and closing, folding and unfolding, elongating, swaying, shading, creeping and standing; all of these define plants as well as any anatomic feature or molecular interaction. We are here to consider plants as design models. Always, and we want to keep in mind the aesthetic value of plants. Yet it makes sense that we want to understand something about their underlying function, because the evolution of functionality, in concert with beauty, grace, and harmony is the miracle of plants.

Looking at a plant we observe its outer facies, its shape and size, its visual nature, its place in the landscape. We may perceive its aroma, either of flowers or leaves, and perhaps we can hear it whisper in the breeze. But for design inspiration we want to go past “biomorphic” shapes. We don’t necessarily want to design leaf-shaped buildings, flower-shaped parks, or packaging that mimics plant ovaries, which grow into fruits. So in these pages I move beyond the popular concept of “biomimicry.” I assert that plants offer us something else, something much more valuable. Plants are radical living elements, the product of millions of years of evolution in the face of adversity. Plants offer us insights into how to make effective designs that have beauty, simplicity, and function. Beauty, simplicity, and function are wrapped up in the body of the plant. Darwin considered plant diversity--the array of physical patterns in plants--as an “abominable mystery.” Let’s harness that mystery for our own designs as we launch into the study of botany.

Introduction

The idea for this project is dedicated to my students at the Boston Architectural College (BAC). BAC students train to become architects, landscape architects, and designers. My course is required for the landscape architecture students at the BAC and it’s a science elective for the rest. BAC students are real problem solvers and the ideas in here are for problem solvers. I was recruited to teach at the BAC because I’ve been communicating about science to non-scientists for a long time. Perhaps in that way I’m a problem solver too, because I my specialty is making science understandable to people without formal scientific training. Most people are interested in what science can tell them about the world but most of my students come into class not necessarily “liking” science. So engaging people in scientific thought and analysis is a challenging goal.

Many of my BAC students are career changers, which I was, and they work very hard to accomplish their degrees, often at the expense of having a “life.” The BAC's concurrent educational program requires students to work in their discipline during the day and take classes at night. You can imagine that my students look and feel their best at five PM on a Wednesday night after battling traffic and finding a parking space on busy Newbury Street in Boston--all at the end of a long day's work. So the experience I have to share with you--an experience that made an indelible mark in my psyche as a teacher-- is an experience unique to the BAC and its students. These are "real" people whose feet are on the ground. Like I said, problem solvers. They're visual learners, quick studies with good brains, designers who grapple with the world of ideas and in particular, scientific ideas. Here's the story of my life-changing experience with my BAC students.

As a botanist I've pondered for years about chloroplasts, the photosynthetic bacteria that live in leaf cells and partner with plants. Chloroplasts, not plants, perform photosynthesis. Chloroplasts share the products of photosynthesis with the plant they dwell in, whose leaves are a kind of solar panel that house the chloroplasts. The plant leaf provides shelter, water, and proper exposure to light, but it’s the chloroplasts, actual separate organisms with their own DNA, that do the productive work of photosynthesis. We know what happens to leaves in the fall. But what happens to the millions of chloroplasts that live in each leaf? Do they die? Do their protein- and mineral-rich bodies (expensive to make and maintain) break apart into their component parts? Are they absorbed and stored somewhere, inactive, in the plant? And what happens in spring? How are chloroplasts recruited to take their place in the growing leaves? Are they somehow taken out of storage? Where do they come from? Are they put back together to function as photosynthetic entities? I've discussed these questions widely with my colleagues and even made inquiries to photosynthesis specialists. No one, especially me, has been able to come up with an answer. That is, until I brought the questions up one night to my BAC students.

It was the end of the semester, a warm night in May. It was time to go home. Time to call it a day. Instead, I insisted, unwisely I realized at the time, to continue class for a few more minutes. I asked the question, “What happens to chloroplasts in the fall?” And there was silence. Was it a trick question? Something I’d gone over in a flash, never coming back to? Was it something that would show up on the final? My students thought for a moment, quiet, which they always are. I perceived that their problem-solving apparatus had gone into gear and I didn’t break the silence, even after a long minute or two. Finally a student in the B-Arch program raised his hand and suggested, "Didn't you show us twigs last winter that were green under the bark?--I think you said that means they're doing photosynthesis....and if they're photosynthesizing doesn't that mean there are chloroplasts under the bark and in buds all winter?"

In a few simple sentences this student answered a questions that had bugged me for years. Practical, to the point, yet somehow inspired to think way outside of his design box. How he came up with the answer I don't know. How did he put his finger on the answer so effectively? So elegantly? Lecture notes? Field experience? Whatever, he cut through the complexities that had somehow hampered me from answering it the question. His answer made a statement pertinent to design—something we had been discussing all semester: Plants are structurally simple organisms that function in complex ways.

What magic motivates my students to think about plants as models for design? How is it that they use a science course as inspiration for their practice? How do they bridge the gap between academics and work, science and design, and how do they do it in a classroom when most of the world is relaxing with a glass of something red?

In these pages I’ll explore botany for designers much as I do in class. With illustrations, questions, comparisons. To get the most out of my class I ask my students to observe, document, and analyze nature. If these pages inspire you to do the same, I will have achieved my goal.