How to know the trees; an illustrated key to the most common species of trees found east of the Rocky mountains, with suggestions and aids for their study.

How to know the weeds

How to Know the Trees: All Illustrated Key to the Most Common Species of Trees Found East of the Rocky Mountains, with Suggestions and AIDS for Their Study (Classic Reprint)

Living things, how to know them; an illustrated key to the phyla, classes and more important orders of plants and animals with suggestions for studying them.

How to know the water birds; pictured-keys for determining the water birds of the United States and Canada, with maps showing their geographic distribution, and with other helpful features

Plant Families - How to Know Them

How to know the land birds; pictured-keys for determining all of the land birds of the entire United States and southern Canada, with maps showing their geographic distribution and other helpful features.

How to Know the Land Birds: Pictured Keys for Determining All of the Land Birds of the Entire United States and Southern Canada