Some links that will be helpful in preparing for this fieldtrip and in teaching the students about plants include:
This is the official website for the Fullerton Arboretum. You can find general information here and also background information about how the arboretum was started. There is also a map about the grounds of the arboretum and some descriptions about its different plant collections.
This website highlights information about how plants are adapted to live in their particular environment.
Here we see some books whose topics are plants and gardens.