They are under your feet and over your head; in your backyard, your refrigerator and faraway destinations. Plants are everywhere, and since people first learned that some plants are good to eat and others are poisonous, they have been trying to identify plants. With 400,000 plant species worldwide--and many yet undiscovered--learning the exact name of that pesky weed or that stunning flower draws on botany, the study of plants, and taxonomy, the study of classification.
On his website Backyard Nature, naturalist Jim Conrad reminds budding naturalists that all they need to get started identifying plants is a field guide, many of which can be borrowed from the public library. He adds that the Internet has made plant identification easier, as universities, botanical organizations and hobbyists make information and images widely available. Writing notes, making sketches and taking photographs will help you to remember the details.
Closely related species tend to look alike, and plants are often classified based on observable structures, so honing your powers of observation is essential when learning to identify plants. Botany professor William A. Niering, in the "Audubon Society Field Guide to North American Wildflowers," notes that plants are classified based on the shape and structure of their leaves, the number and arrangement of their flowers and, of course, color and size. However, don't just rely on sight. Some plants have distinct smells or leaves that are waxy or fuzzy to the touch. All of these details are important when identifying a plant.
All plants belong to the plant kingdom, the broadest taxonomic classification. Within that kingdom, plants can be divided into four major phyla: mosses, ferns, gymnosperms and angiosperms. Identifying a plant should begin by determining to which phylum it belongs. Mosses, or bryophytes, are distinguished by their lack of vascular tissue, meaning that they must stay small to survive. They lack roots as well, although they can grab hold of rocks and tree bark with tiny filaments. Ferns have vascular tissue, allowing them to grow larger, and reproduce with spores. There are two types of seed-bearing plants: gymnosperms and angiosperms. Gymnosperm comes from Greek, meaning "naked seed." Its seeds are not protected by flowers or fruit but grow exposed on cones, like conifers or palm trees. Angiosperms are the flowering plants. Their seeds form inside an ovary.
Once you know the plant's phylum, identifying the family to which it belongs will help provide valuable clues to identifying the precise species. Plants belonging to the same family usually have important traits in common. For example, members of the mint family have square stems, leaves occurring in pairs opposite each other and a strong odor.
Once you've found a possible species name for the plant you're trying to identify, additional research will help you to confirm the accuracy of your conclusion. First, determine the plant's geographical range. While it's not impossible for plants to be carried to areas they don't typically inhabit, if the plant is common in your area, the species should fall in your geographical range. Next, learn more about its habits, such as seasonal flowering or preferred habitat. A spring ephemeral that lives in the forest, for example, is not likely to be found blooming in the fall in a vacant lot.