Microbial endophytes (fungi and bacteria that live within plant cells) are understood to play a significant role in the ecology of their plant hosts, but little is known of their response to climate change. Now, the diversity of microbes can be easily quantified with DNA sequencing, but there is little historical data with which to compare modern findings. Herbarium specimens may provide an historical record of bacterial and fungal endophyte communities, allowing for study of how endophytic communities may have changed over time. In this study we analyzed changes in endophyte biodiversity over the past 50 years in the Guadalupe Mountains, a biodiversity hotspot in Texas spanning seven ecoregions. We sample roots and leaves of herbarium specimens from several species collected from Guadalupe Mountains National Park. For each species we take samples from both an older specimen collected from 1973-1977 and from a recent specimen collected in 2022. We extract and sequence DNA from herbarium specimens and analyze data using standard microbiome data processing pipeline. We characterize endophyte species richness and phylogenetic relatedness across time points and plant host species and contribute to building a better understanding of the change in composition of plant microbiomes over fifty years.