Walk through any garden, park or roadside in India or Thailand and you will see an amazing variety of plants. Some are tiny and soft, some are bushy, and some tower above the houses. Scientists group plants by the size and nature of their stems. Herbs are small plants with soft, green, thin stems that bend easily. They usually live for only one season. Coriander, mint, spinach, tomato, wheat, rice and holy basil are herbs. Shrubs are medium-sized plants with hard, woody stems that branch out close to the ground, giving a bushy shape. Rose, hibiscus, jasmine, lemon and tulsi that has grown old are shrubs. Trees are tall plants with a single thick, hard, woody trunk that branches high above the ground. Mango, neem, banyan, teak, coconut and tamarind are trees. They can live for hundreds of years.
Not every plant fits neatly into these three groups. Climbers, such as money plant, grapevine, bitter gourd and pea, have weak stems that cannot stand on their own, so they use tendrils or twining stems to climb up a support. Creepers, such as pumpkin, watermelon and sweet potato, have weak stems that spread along the ground. The famous banyan tree of India grows extra roots from its branches that hang down and become new trunks, so one tree can look like a small forest. Grouping plants this way helps botanists talk clearly, helps farmers plan fields, and helps gardeners know how much space a plant will need. Diversity, the variety of living things in an area, is one of the biggest ideas in this chapter and you will meet it again with animals.
Example: Go outside with a notebook and find at least eight different plants. For each one, gently feel the stem and note whether it is soft and green or hard and woody, whether it branches near the ground or high up, and roughly how tall it is. Classify each as herb, shrub, tree, climber or creeper and draw a quick sketch. Expected result: most small garden plants and grasses are herbs, flowering bushes are shrubs, and anything taller than a house with a single trunk is a tree. Count how many groups you found in one small area to see diversity for yourself.