You think plants are dull? What about a giant flower that's three feet wide, has no roots, leaves, or stem, and smells horrible? Or a teeny-weeny plant that produces a figlike fruit that weighs a little more than a grain of salt? Or how about a fern in your backyard that dinosaurs used to eat? Read on....
In ponds across North America, you'll find plants so small it takes a magnifying glass to see them. When thousands of these flattened, oval-shaped green bodies congregate, they form a coating of green film on the water surface. It may look like algae, but it's not. Scientists call it Wolffia, but it's better known as duckweed. It got its name because ducks and other waterfowl eat it.
Wayne Armstrong, a professor of biology at Palomar College in San Marcos, Calif., says it takes about 25 Wolffia plants, placed side by side, to equal one inch. One plant is "roughly two to three times as large as a grain of table salt." The plants lack true roots and are easily moved across the water by the wind. That's why you find them in masses along pond edges. Millions of the plants may grow in a small pond.
Duckweed produces the world's smallest flower and tiniest fruit. The flower lacks petals and sepals. It's nothing more than a single stamen and pistil in a pouch on top of the plant.
The flower produces a tiny fruit that Mr. Armstrong describes as a "miniature fig with just one seed." It would take about 40 fruits to equal one inch. (That's half the size of the plant. Can you imagine an apple that's half the size of a tree?)
The fruit weighs 1/400,000th of an ounce. A grain of salt weighs slightly less. But the fruit of a duckweed is hard to find, because it rarely yields any.
Duckweed occasionally reproduces using its minuscule flower. But most of the time it reproduces by budding. Buds grow into exact copies of the parent plant. The new plants then break off and establish themselves. This process happens relatively quickly. In the case of a particular species (Wolffia microscopica), budding can take place in 30 hours!
Armstrong has done some interesting calculations about this. If one duckweed plant could keep reproducing nonstop every 30 hours for four months, a nonillion plants would result.
A nonillion is a one with 30 zeroes after it. A nonillion duckweed plants would equal the volume of the Earth!
It doesn't take a dark, stormy night to bring out these ghostly creatures - just a nice patch of decaying leaves in a shady woodland forest. If you live in North America or Asia, you may have already seen Indian Pipes.
Its scientific name is Monotropa uniflora. The plants are totally white (sometimes they have a pinkish tinge) and waxy in appearance. No more than 10 inches tall, they grow in tight masses. Each plant has one odorless flower with four or five petals. The blooms look like tiny bells hanging down from a scaly stalk. Flowering begins in June and ends in early September.
Indian Pipes lack the chlorophyll (KLOR-uh-fill) that plants use to make their own food. Instead, they get their food from trees. But they don't do it all by themselves.
According to Karen Snetselaar, assistant professor of biology at St. Joseph's University in Philadelphia, these plants team up with fungi living in the soil. Here's how it works:
Indian pipes attach their rootlets to a fungus. The fungus, which is also unable to make its own food, is already attached to the roots of a nearby tree. Trees make their own food through photosynthesis (fo-to-SIN-thuh-sis). In photosynthesis, sunlight, water, and carbon dioxide - a common gas - are combined to make sugars that provide food for the plant. (Maple syrup is actually tree sap that has been boiled down to concentrate the sugar.)
The fungus absorbs some of these sugars from the tree roots. The Indian Pipes take their share from the fungus.
A LIVING FOSSIL
Ever wonder what it was like in dinosaur times? Although you can't see an entire prehistoric landscape, you can view at least one of the plants that grew back then. You may already have seen one while walking in open woods or along stream banks. It's called horsetail or Equisetum (eh-kwee-SEE-tum). Scientists estimate that it's been around since the Paleozoic Era, about 350 million years ago.
When dinosaurs roamed, horsetails had stems more than two feet thick and grew to be 100 feet tall. Today, the largest known horsetail is Equisetum giganteum, found in the American tropics. Growing to 12 feet high, its one-inch-diameter stems are too weak to support the plant by themselves. This horsetail has to lean on surrounding plants for support. The common, North American species grow to be about three feet tall.
Horsetail looks peculiar. Each straight stalk is green with thin, dark-brown or black bands that mark segments. That's it. No leaves, no branches, no flowers. At the top is a cone-shaped structure where spores are produced. Spores are microscopic structures used for reproduction.
It's highly unlikely you'll see just one horsetail. The plant is very aggressive and quickly forms large clumps. Its roots can go down 30 feet into soil and reappear up to 20 feet away. That's one reason the plant has survived for so long.
Horsetail has another unique characteristic. It contains a large amount of silica - up to 40 percent of the total weight of the plant. Silica is commonly found in sand. This makes the plant very abrasive.
Native Americans and early settlers discovered a good use for horsetail. They bundled stalks together and used them to scour pots and pans. Some natural cleaning products still include horsetail as an ingredient. Many artists today use it to polish wood and metal sculptures.
Dinosaurs may have eaten horsetail. Do you suppose it kept their teeth nicely polished?
BIGGEST AND SMELLIEST
Southeast Asia is home to the world's largest flower, Rafflesia arnoldii, known as the "stinking corpse lily." Endangered and rare, this is probably one of the oddest members of the plant world. Each plant produces one, three-foot-wide, meat-red flower with raised white spots. And that's all it is - one enormous bloom. Unlike green plants, which make their own food, Rafflesia is a parasite. That means it must obtain its nourishment by living off another plant. In this case, it's the woody stem of a grapelike vine known as Tetrastigma. This vine has to be very strong. Rafflesia can easily weigh up to 36 pounds!
A flower this amazing must have an incredible smell, right? Yes. In fact, it stinks. It reeks like rotting meat. Only carrion flies and beetles are attracted to it. Since these insects eat dead animals, they think the awful smell means "food."
But the plant has tricked them. Instead, the insects gather and spread its pollen to other Rafflesias.
Each plant produces more than a half-million seeds. This large quantity is important to its survival, since it's not likely a seed will end up on a Tetrastigma vine, the vine the plant needs in order to grow.
That's where wildlife come to Rafflesia's rescue. Squirrels, ants, small mammals, even elephants may pick up seeds on their skin and feet. Should they happen to step on a Tetrastigma vine, the seed may lodge in a crevice. When this happens, the seed begins to grow.
One more thing: Did you wonder about the name of this plant? The Rafflesia was named for its European discoverers. Back in 1818, Sir Thomas Stamford Raffles, an explorer and naturalist, and Dr. Joseph Arnold discovered the plant and named it after themselves.
A TREE FOR THE THIRSTY
When was the last time a plant offered you a drink of water? If you visit Madagascar, the Traveler's Palm could quench your thirst. Ravenala madagascariensis was named the Traveler's Tree or Palm because thirsty voyagers found the base of each of its fronds held up to a quart of rainwater.
The plant grows up to 40 feet tall and has a palm-tree-like trunk. Although it looks somewhat like a palm, it is actually a member of the banana family. Its shiny, broad leaves grow in a fanlike pattern. Each frond may be 14 feet long.
Christine Bock, lead horticulturist at the Tennessee Aquarium in Chattanooga, describes the plant's flowers as "drab, leathery structures with nectar located at the base." Some plants can self-pollinate. The Traveler's Palm cannot. Instead, the plant has "a unique solution to this problem," she says. It produces large quantities of sugary-sweet nectar to attract pollinators to it.
But there's a catch. Not everything with a sweet tooth can obtain the nectar. In fact, the "Madagascar black lemur is one of the few animals strong enough to open the flower," Ms. Bock says. "When it pulls the flower apart to drink the nectar, the palm pollen adheres to its head."
Looking for more nectar, the lemur moves on to another palm, dispersing the pollen that stuck to its fur. This works well for both parties - the Traveler's Palm is pollinated, and the lemur satisfies its sweet tooth.
(c) Copyright 2000. The Christian Science Publishing Society