Montanoa guatemalensis was first described by Robinson and Greenman in an article for the Proceedings of the American Academy of Arts and Sciences in 1899. M. guatemalensis is a tree growing up to 15 m tall with variable leaves covered in whitish hairs as they age. The outer ray florets are white and the inner tube-shaped disc florets are yellow. Achene type seeds are dark brown-black. For more information, see the diagnostic description below.