Trees of Eastern North AmericaGil Nelson, Christopher J. Earle, Richard Spellenberg, David More, Amy K. Hughes · First published 2014Open the Tome
Trees of Western North AmericaRichard Spellenberg, Christopher J. Earle, Gil Nelson, David More, Amy K. Hughes · First published 2014Open the Tome
National Audubon Society field guide to North American wildflowers, western regionRichard Spellenberg · First published 1994Open the Tome
The Audubon Society field guide to North American wildflowers, western regionRichard Spellenberg · First published 1979Open the Tome
