This article concerns the species composition, life forms and community ecology of tropical alpine vegetation at a site adjacent to Cajas National Park, southern Ecuador. We sampled plant communities located between 3700 and 3970 m elevation in an upper montane basin. Twenty-one plots were inventoried, and several quantitative techniques were utilized to determine how plant community patterns vary with elevation, slope and various terrain characteristics. One hundred and thirty vascular plant species were found within the study area. The plant community patterns and distribution of life forms differed significantly between valley bottoms and hill slopes, presumably due to soil changes and topography. Additionally, valley bottoms include numerous locally rare plant species and important wetland habitats that may be susceptible to trampling; the slopes appear to be particularly vulnerable to burning. These concerns need to be addressed if this park is meant to protect native plant diversity.