The California Native Plant Society's policy on collecting plants for educational purposes is well worth reviewing. More and more the conservation ethic is to collect in the wild only when it serves a long-term research purpose, such as documenting what occurs in an area that is proposed for development, or discovering what grows in an area that has not been much explored. But these collections must be placed in permanent storage in order to serve their documentary purpose, and once in a scientific collection they can continue to contribute to science in many other ways. Getting Started Where to collect It is legal to collect plants only with the permission of the owner of the property on which they are found. Government agencies that manage land generally grant permits only to researchers working for an approved institution, such as a university.
Private landowners are often willing to allow judicious collecting if asked.
Do not collect illegally. What to collect If the plant is small, take the whole thing, roots and all, or even several of them. If large, get a branch about 10 inches long, with leaves, flowers, and fruits, if possible. Even an old empty seed capsule can be helpful if that's all you can find. Information needed The date the plant was collected and the location as exactly as possible.