The breadth of the Mexican Transition Zone as defined by its flowering plant generic flora.

Biogeographic regions are defined by taxa with similar distribution patterns. Flowering plants have been widely used to propose biogeographic regionalization schemes because of shared historical or ecological factors that determine their distribution. The Mexican Transition Zone represents the boundary between the Nearctic and Neotropical kingdoms; however, there is no general agreement about the limits and extent of this region.

[Penile fracture with associated urethra lesion: case report and bibliographic review].

Objective: Penile fracture is a rare lesion that occurs almost exclusively during erection. This lesion may be associated with rupture of the urethra in 20-30% of the cases. We describe a case that has been treated at our institution and review the literature.