Grasses and their products can crop up in unlikely places – necklaces of the shiny white Job’s tears (Coix lacryma-jobi), citronella insect repellent from Cymbopogon citratus, plastics from maize (Zea mays) starch, to name but a few.
All round the world, communities found ingenious ways of using readily available plant resources to meet their needs. Perhaps the most remarkable is the light bulb, with a filament of carbonised bamboo, developed by Thomas Edison, the American inventor.

Cornucopia

Corn, or maize as many people know it, is the source of materials used in the manufacture of products as diverse as tyres and medicines. In Mexico and Central America, where it is native, maize (Zea mays) has long been cultivated for its starchy kernels which are ground to flour for tortillas and other flat breads. Today, corn kernels are also eaten fresh or as popcorn and cornflakes. They are an important animal food.

Corn starch, corn syrup and corn oil, together with dextrose or dextrin, are all derived from corn kernels. A paste of corn starch is used to coat aspirin, but as a powder it is sprinkled into tyre moulds to prevent the rubber sticking. Sorbitol, produced from dextrose, is a low-calorie sweetener for toothpastes. Corn syrup is an ideal nutrient for antibiotic culture, features in theatrical make-up and in the manufacture of explosives.

New corn-based materials under development include plastics, biodegradable packaging materials and even a silk-like fabric.

Grass power

Generating electricity from grass might seem far fetched, but scientists have identified various grass species that are potentially useful sources of renewable energy. Since they discovered fire, people have burnt plant material for heat and light. In power stations, burning crop wastes or energy crops provides the heat to convert water to steam. This drives a turbine that generates electricity. Fuel crops can even be turned into gas by a special heating process.

Some UK power stations already use wheat straw (previously considered an agricultural waste) for fuel, as well as specially grown Miscanthus. Miscanthus species are fast-growing perennial grasses that yield large quantities of burnable dry matter. Other energy crops include switchgrass (Panicum virginatum) in the USA and reed canary grass (Phalaris arundinacea) in Sweden.

Botanists in Kew’s herbarium have been studying Miscanthus to identify the genetic make-up of the forms grown in the UK. Kew’s Miscanthus collection may be used to breed more productive varieties.