If you walk by even the simplest garden, you'll see plants that were transported there from other continents. If you walk by a field or an orchard, you'll definitely see foreign plants brought close to help people survive or just enjoy themselves. It seems simple now, but the ability to do this easily changed nearly everything about the Earth and the way people worked it. And it all came from remarkable scientific discovery.
How do you keep an orchid alive on a ship that exposes it to salt spray, blazing sun, tropical gales, northern storms, and barely any fresh water for months at a time? You don't. Although botanists traveled the world for centuries, taking clippings, collecting seeds, and stowing plants on ships, they were lucky if anything ever made it back alive. Plants grew where they grew, and if you wanted what they could produce, you dealt (often unpleasantly) with the people who lived there.
And then Nathaniel Bagshaw Ward put a moth chrysalis in a sealed glass case to preserve it. Months later, he was unpleasantly surprised to see some mold growing in the case, but intrigued when he saw seeds germinating on it. He put the bottle on a window ledge, but kept an eye on the seeds. The seeds turned into ferns and grass. Ward followed their progress for the next four years and was amazed to see them keep alive and healthy while the plants in his outdoor garden were choked by the London smog. When the seal finally rusted and cracked, the plants died.
He kept testing. He put mold in a case. He put plants and mold in the case. He put plants and birds in a case. He eventually built up a collection of 25,000 plants in sealed glass cases. When he saw an opportunity for a real test, he had a carpenter build another case, in which he sent plants from England to Sydney, Australia. The half-year-long journey by sea didn't kill a plant, even without the addition of water to any of the cases. Plants are remarkably self-sufficient in a closed environment. They take in water from the soil during the day, but excrete it at night. In a glass case, the water condenses and runs down the glass back into the soil. The glass also protects the plants from any adverse conditions outside. All they need is a little initial water and sunlight shining down on the case every day.
The discovery was a revelation. Suddenly, people were able to take a plant from one continent, and bring it to another. Once it arrived, they were able to keep it alive throughout bad winters or hot summers that would otherwise have killed it. A cutting could be taken from the case and experimented on, while the original plant stayed safe.
This allowed people to terraform their environments to a degree never before achieved. It wasn't just that people in cities could admire a pretty foreign plant in their parlor. The British could ship tea plants across continents from a hostile nation and transplant them to a country where they could be mass-grown. Fruit trees could be transported across climates that would kill them into foreign places where they would thrive. A Peruvian tree was known to produce quinine — a defense against malaria. Malaria was, and is still, a terrifying killer. It could be stemmed only with the medication found in Peru. Once it was put in a case and shipped out, malaria could by prevented everywhere. Plants that could provide medicine, nourishment, or just enormous profit, could be taken wherever they were needed (or could be grown en masse) regardless of where they originated.
Obviously nowadays, everyone's more worried about invasive species getting to their shores than dying before they make it. But there was a time when people were — sometimes literally — dying to try to transplant much-needed plants across the ocean. The Wardian Case, as it came to be known, completely changed the surface of the planet. Its ability to preserve and transport plants may have caused one of the largest terraforming movements the world will ever see.