Northwest of Lake Izabal, Guatemala, G. C. Jones and L. Facey collected in 1966 abundant material of what we have called
Macromitrium crumianum Steere & Buck. This new species is characterized by linear-lanceolate leaves which are long acuminate, with leaf cells which
are smooth and linear throughout, a smooth seta and capsule, and a naked calyptra. It is most closely related to
M. dubium Schimp. of the West Indies and perhaps also to
M. leprieurii Mont. (
M. dussii Broth.) of the West Indies, French Guiana and Suriname.