I ventured out this morning into lingering fog after rain yesterday and overnight. I found endless delight in all the water droplets, like finely polished gems, that had collected on the surfaces of leaves and at their tips. My photograph today is the largest droplet I saw on my walk, suspended at the curled tip of a Chinese privet leaf.
One drop of water, poised on a curled plantain leaf, waiting for the next gust of wind.
On my daily walk down Piney Woods Church Road today, I relished the warm, moist air, evocative of a rain forest. Everywhere I was bedazzled by sundry shades of green — saplings, shrubs, and vines all crowding for space along the roadside. In this image, one vine supports another as they scramble for sunlight.
Today was my first day “in the field” with my new Olympus OMD EM5 camera. I still look fondly upon the Sony CyberShot that I used for the first 127 days. But this new camera leaves me amazed with the vividness of color and crispness of images possible. I am still figuring it out — there is so much to learn! Today, I share this image of a leaf miner’s “scrawl” on a leaf of muscadine grape, reminding me of scrimshaw work.
On my way home down Piney Woods Church Road, I glimpsed this spider web along a barbed wire fence. The spider evidently used a dried plant stem as a frame, crafting its web within that spiral.
After taking some photographs of the tulip poplar blooms today, I stopped at the home of dear friends to chat over a beer. I missed the sunset, but on my way home, I stopped to take a post-sunset photograph of an old barn against the horizon.
Now that all of our deciduous trees are in leaf, and roadside ditches and forest floors in the Georgia Piedmont are green with life, it is a marvelous time to take a walk and see how many different leaf shapes you can find. Many shapes are particular to a certain kind of tree, shrub, or vine; some, like that of the maple, have even been celebrated on a country’s flag. There are the three jagged leaflets of poison ivy, and five of Virginia creeper; the many lobes (rounded or jagged) of the oaks; the tulip-shaped leaves of the tulip tree tree; the five-pointed star of the sweet gum; and the heart-shaped leaves of the wild yam. Some plants cannot settle upon one leaf shape, but instead have several. Leaves of the sassafras tree can be simple ovals, shaped like mittens, or have three broad, blunt lobes.
It is one of those wonders of the natural world that there is such diversity in the shapes of leaves. As one website on leaf shapes remarks, “Plants have leaves in many different shapes – the thicker the book you refer to, the more leaf shapes they seem to find.” The various classifications and permutations of shape form an arcane language, limited to a handful of botanists and elementary Montessori school students: terms such as runcinate, trifoliate, cordate, digitate, and deltoid. Although the words may be unfamilar, they describe the shapes of leaves encountered all around us: dandelion, clover, morning glory, maple, cottonwood. Beyond terms for general shape are further classifications for leaf form: toothed or untoothed, simple or compound, entire or lobed. Finally, even though one set of terms might be used to classify a leaf from a particular species of plant, some plants, particularly oaks, have leaves that vary considerably while keeping to generally the same overall shape.
Why? Why is there such diversity in leaves? What makes one leaf angular and another rounded, one leaf wide and another narrow? These are the kinds of questions wondering children might ask, after being satisfied with a general explanation for the color of the sky and the forces causing the wind to blow. And, like most questions children generate, the answer is not an easy one. Indeed, there is no one clear explanation out there. Only a few days ago, a physics blog reported a new theoretical model that purports to explain all leaf shape variation as an incidental effect of the different patterns of veins in the leaf.
Some aspects of leaf shape have been explained based upon comparing tropical forest plants with temperate forest ones, such as those here in Georgia. A visit to a tropical rainforest, or a greenhouse full of tropical plants, will reveal that most tropical leaves are thicker than temperate ones, as well as more rounded and smooth-edged (untoothed). Tropical plants retain their leaves for years, while deciduous plants in Georgia forests all keep their leaves only for one season. As a result, tropical leaves are sturdier than temperate forest ones, and therefore thicker. Thinner leaves require less energy to produce, and are more effective at gas exchange needed for photosynthesis. However, there is a cost of having thinner leaves: they are not as sturdy, particularly in areas distant from the major leaf veins (which provide structural support for the leaf). So those distant areas are simply done away with, resulting in lobed leaves like those of the white oak. The lobes (or teeth) of many leaves of Georgia plants also help to reduce wind resistance (and the damage that could result from it). Also, botanists have noticed that lobed or toothed leaves can permit sunlight to reach leaves beneath them, so perhaps the indentations help the plants filter sunlight down to leaves on their lower branches or stems.
Ultimately, we simply do not know why there are so many leaf shapes are out there, and how (if at all) a star-shaped leaf might better serve a sweet gum tree’s needs than the compound structure of ovate leaflets of a hickory. It is humbling and perhaps even a bit comforting, though, that something so commonplace as the forms that leaves take has managed to remain so mysterious for so long a time.
This article was originally published on May 8, 2010. The original photo has been replaced with a recent one I took, of a sassafras leaf.
I was drawn to take this photograph by the line of tiny water droplets, like miniature glass marbles, cradled atop a blade of grass. While taking the photograph, I noticed that there also seemed to be water droplets along the underside of the grass blade. At home, viewing the image in Picassa, I was surprised to see these globes of water hanging so delicately, like suspended worlds. I included two near-identical pictures below because the second one includes an image of the photographer (the first one includes part of the photographer’s hand, but not his distinctive hat). Can you spot this unintended “selfie”?
On a cold and soggy day, I walked the length of Piney Woods Church Road, I could see and feel the elemental presences of wind and rain joining me on my journey. Gusts of wind tugged on horsehair snagged on a barbed wire fence; raindrops feel on roadbed leaves, newly fallen in the morning wind.
Not long after I set out for Piney Woods Church Road, the rains began. I was ill-equipped for a deluge, having left my camera bag at home (trusting too much in Doppler radar maps which showed precipitation still an hour away). I quickly focused my attention on certain shots — mostly particular wildflowers I noticed in bloom. Fortunately, the rainfall remained fairly gentle, though it didn’t prevent me from getting fairly soaked. Toward the end of my walk, my camera still functioning and my body rather drenched, I eased up a bit and began letting images find me. This is one of the products of that last part of my walk. Droplets cover a new sweetgum leaf that hangs like a curtain in front of the road I have just walked.
