There can be few so commonly misquoted quotes which are so universal, so vital and so imperfectly understood as the famous ‘all flesh is as grass’. The evangelist was commenting, no doubt, upon man’s ephemeral nature—as tenuous as, in another context, are ‘theof the field’. Such early references to the world of plants are legion in the writings of all cultures reflecting man’s consciousness of the distaff side of animate things. Yet in leaving behind his early beginnings, in developing a hierarchical and highly differentiated series of civilizations, innate consciousness that all flesh it grass has not been at all generally replaced by knowledge of the scientific truths that make it more valid now, in a period of frighteningly rapid population increase, than ever in the past. Plants, and plants only, possess the amazing ability to make, synthesize, produce—indeed create, out of the very air—the complicated foods that are the source of the plants’ own energy and the source, too, of animal life as we know it on this planet.
Such a claim may appear a fulsome hybrid between the mediaeval elixir of life and a science fiction parody. Yet it is easily, if not simply justified. The omnipresent ingredients of gaseous carbon dioxide and of water, with sunlight as the energy-source are built up into starches and sugars which are used in a wide range of forms as the basic growth material of plant bodies. And plant bodies are the basic growth material in the unbroken organic chain that stretches from amoeba to man. The process is called. But why plants? The simple answer is their possession of what became so verbally debased when the toothpaste and deodorant manufacturers got hold of the name—’nature’s green’—chlorophyll.
In the cells of plantand other green parts are small organs, that are unique to plants, called chloroplasts and which control the chemical reaction that is continually taking place in the presence of light (even artificial light). The essential ingredient, chlorophyll, acts as a chemical catalyst—a facilitator which remains itself unchanged. All normal wavebands of light can be used except green: this, being reflected, causes us to ‘see’ plants as green and to take such greenness as the essential character of the plant kingdom, which both visually and chemically, it actually is.
This basic characteristic—the possession of chlorophyll—is that which defines a plant except in a few very specialized cases. Conversely (with a few exceptions) any living organism that is without them must be an animal. Conventional definitions that members of the animal kingdom are characterized by movement are altogether too simplistic: plants move, in response to a range of stimuli, as well. No, the difference is that animals cannot photosynthesize; they have no chlorophyll. Hence, in truth, all flesh is grass.
It is, of course, unhelpful merely to refer to the plant kingdom as a unit because of its one great universal denominator. The diversity of form is enormous from the mass of microscopic, often unicellular, plants which make up (with a world of equally microscopic animicules) the green scum in pondwater, to trees almost as high as the spire of Salisbury Cathedral or as old as the Ark—and still living. Such diversity, which is, after all, the response to environment throughout evolutionary aeons, demonstrates the all-pervading success story of plants. There is, and as long as life has existed on this planet, there always has been, a plant for all seasons and for all sites.