Tiny plants in plastic pots, each carefully labeled, cram a South African greenhouse. Each is the evidence of at least one crime. These are strange plants without typical stems or leaves. Some look like greenish thumb-tips, others like grapes or rounded stones. Some sprout small, bright flowers. Few are more than an inch tall. I've agreed not to disclose this location because the plants, confiscated from poachers and smugglers, are valuable and could be re-stolen by the same criminal networks that first dug them from their natural habitats to traffic overseas. The plants come from a vast, arid, and thinly populated region that ecologists call the Succulent Karoo biome. It's about the size of Kentucky and extends from southwestern Namibia into South Africa's Northern Cape and Western Cape provinces. Most people would consider the Succulent Karoo a desert - it's certainly hot, especially in summer, and gets very little rain - but it's bursting with biodiversity. The region's vegetation is dominated by succulent plants, many of which take on bizarre, bulbous shapes for camouflage or for conserving water and periodically bloom in vivid yellows, oranges, reds, purples, pinks, or whites. Botanists have recorded about 6,400 species of native plants here, about 2,500 of them found nowhere else - far more than any other arid region of comparable size. The Succulent Karoo also has numerous unique insects and reptiles, including the world’s smallest tortoise species. About 8 percent of the South African part of this biome is formally protected.