Kenny Perda, age 12, of Medford, Okla., for his question:
Why do wheat and barley have beards?
noses are red and violets are blue because their insect friends are color conscious. Green leaves rise above ground to soak up the sunny air. Roots probe doom to soak up the rich moisture in the crumbly soil. There's a good reason for every device in the plant world. The seeds of wheat and bearded barley have whiskers to hitchhike runaway rides from home.
The earth provides special places for more than 350,000 different plants. Each spe¬cies is designed to manufacture its or m food, to produce offspring and to cope with a few other survival problems. Throughout the plant world, there are millions of different devices to cone with these few basic problems. For example, the seed bearing plants have countless built in devices to avoid over crowding for the next generation.
This botanical department is called seed dispersal. Almost every seed bearing plant has its own ingenious device to scatter its seeds so that the next generation has room to grow. This is why the wheat and the bearded barley provide their seeds with spiky whiskers.
Many plants depend on the wind to graft their seeds to new places. The seed of the sycamore maple tree has two papery wings to glide on the breezes. The dandelion seed drifts on a feathery parachute. Other plants depend on water to float their seeds to new homes. The coconut has a thick fibrous coat to keep it afloat while ocean currents raft it frown island to island.
Other plants use pea shooter devices to scatter their seeds. When the squirting cucumber is ripe, its shell pops open with a jerk and squirts its seeds as far as 20 feet.
Some plants depend on animals to carry their seeds to faraway places. When a bird flies off with a cherry, he may drop the seed in the neighboring orchard. When he eats a whole raspberry, the tiny seeds are dropped later with his body wastes. A prickly burr is a born hitchhiker. When a sheep brushes by, it hooks onto his fleecy coat.
Wheat and barley grow tall stems and stack their seeds in neat rows at the top. Each seed is sheathed in a papery hush. The barley and some wheat husks have long bristles called awns. These add the whiskery beards to the seed packages. As they ripen, the arms become very dry and stiff. Sometimes the bristles hitch rides on animals and passing people. Then they fall off, the awns help to anchor the seeds in the soil, perhaps in unoccupied territory far from home.
Wheat and barley are cereal grasses that sprout and produce seeds during one short summer season. For countless ages mankind has selected strains with the fattest seeds. This tends to handicap the natural methods of seed dispersal used by their ancestors. Some fancy wheat strains have useless little arms or none at all. Like corn, they depend on farmers to solo their seeds. But the tame barley kept its arms. This is why a few seeds always escape from the fields and pop up along the waysides.