Show somebody a painting of a verdant, botanically explicit forest with three elk grazing in the middle and ask what the picture is about, and the average viewer will answer, "Three elk grazing." Add a blue jay to the scene and the response becomes, "Three elk grazing under the watchful eye of a blue jay."
What you're unlikely to hear is anything akin to, "It's a classic temperate mix of maple, birch and beech trees, and here's a spectacular basswood and, whoa, an American elm that shows no sign of fungal infestation and, oh yeah, three elk and a blue jay."
According to Peter Raven, director of the Missouri Botanical Garden, many of us suffer from an insidious condition called "plant blindness." We barely notice plants, can rarely identify them and find them incomparably inert. Do you think that you will ever see a coma as vegetative as a tree? "Animals are much more vivid to the average person than plants are," Raven said, "and some people aren't even sure that plants are alive."
But the antidote to plant apathy is at hand. As an unusually cool, sodden April in the US edges toward May and spring's cheeky blooms can be bridled no longer, botanists urge everyone to venture outside and check out the world through nature's rose-colored glasses — and the daffodil, cherry blossom and lupine ones, too. If this view doesn't move you, you're pushing up daisies.
As it happens, plants are not only alive in their own right. They are also the basis of virtually all life on earth, including ours. The core feature of planthood is autotrophy, that is, the happy ability to make one's own food. Plants essentially eat the sun, transforming solar energy into sugars and starch through the stepwise enzymatic stitchery of photosynthesis. Animals, by contrast, are heterotrophs, defined by their need to devour other organisms — the hard-won fruit and fiber of the suneaters, or the once-removed flesh of herbivores.
Moreover, because plants release oxygen as a byproduct of photosynthesis, plants also give us aerobes leave to breathe. Our atmosphere is currently about 20 percent oxygen, all of it the bounty of the planet's green-skinned autotrophs. "The most important chemical reaction on earth is photosynthesis," said Robert DeFeo, chief horticulturist for the National Park Service. "We are all parasites upon it."
Essential though plants may be to our survival, Raven emphasizes that they are a radically different form of organism than are animals. Plants and animals have evolved along separate paths for hundreds of millions of years, ever since single cells began pooling their talents into multicelled beings. "Plants have evolved their multicellularity completely separately from animals, and any direct comparisons between the groups are wrong," Raven said. "It's as if plants evolved on Mars, and animals here."
In addition to their caloric self-sufficiency, plants can be envied for their eternal youthfulness. A plant elongates itself through constant cell growth in two zones of its body, at the very tips of the roots, which grow down into soil or other surface to which the plant clings, and the outer tips of the shoots, from which new leaves, flowers and fruits sprout. Whereas an animal, upon reaching maturity, has almost no young cells left in its body, Raven said, "in plants the ends of the roots and shoots are always juvenile, always growing, always babies."
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