Books by Ronald J. Tyrl
Toxic plants of North America
Veterinarian's handbook of toxic plants of North America
Dyes from American native plants
Field guide to Oklahoma plants
The grasses and grasslands of
The grasses and grasslands of Oklahoma
Origin and distribution of pol
Origin and distribution of polyploid Achillea (Compositae) in western North America
Cytogeography of Achillea mill
Cytogeography of Achillea millefolium L. in western Oregon