Understanding botanical distributions and plant biodiversity is of importance to conservationists, and also to others such as land managers, biogeographers and horticulturalists. In Nepal, a globally important biodiversity hot-spot, many plant species are known by field botanists to be under-collected. This study aims to discover the extent of that under-collection and to provide predictions of species distributions that could be used to guide future plant collection surveys. The study collated georeferenced botanical records from herbarium collections made within Nepal and related these to layers of environmental information using the maximum entropy model (MaxEnt). The model provided predicted probabilities for the distribution of twenty-five species in the Rosaceae and Leguminosae families, from which the potential range for each species across Nepal was estimated and mapped. The percentage of each species’ geographical range that has currently not been sampled was then calculated and species richness maps were created to show the numbers of species predicted to appear in different geographical areas of the country. Using this information six locations in the Annupurna region were examined in detail to assess their potential suitability for future botanical collection. The results reveal the extent to which each of the twenty-five species are under-collected in relation to their predicted geographical ranges and illustrate how the derived maps of species richness can be used to assess the suitability of different areas for future botanical collecting by ground survey. The utility of the new species richness mapping will only be determined by the successful (or otherwise) collection of further species records from these areas.