Authors: Francis Whittier Pennell

  • Scrophulariaceae of the Central Rocky Mountain States — Francis Whittier Pennell

    Scrophulariaceae of the Central Rocky Mountain States — Francis Whittier Pennell

  • Scrophulariaceae Of The West Gulf States — Francis Whittier Pennell

    Scrophulariaceae Of The West Gulf States — Francis Whittier Pennell