Weeds affect everyone in the world by reducing crop yield and crop quality, delaying or interfering with harvesting, interfering with animal feeding (including poisoning), reducing animal health, preventing water flow, as plant parasites, etc. Weeds are common everywhere and cause many $ billions worth of crop losses annually, with the global cost of controlling weeds running into $ billions.

The anatomy of plants is generally well understood, but the examples used for explanations in most books are often restricted to non-weed species. Weeds have many features that make them more...