Smith’s fungus-growing ant (Trachymyrmex smithi) is common in the mesquite coppice dune habitat in the northern Chihuahuan desert. We completely excavated several nests near El Paso, Texas in the fall of 2005, and Summer and Fall of 2006. Plaster-casts were created to explore the subterranean architecture of the nest. During the excavation we measured such parameters as: fungus cavity depth, size, location, and over-all structure of the nest. All individuals of the colony were collected to ascertain colony population and caste demographics. When “queens” were found, they were taken to the laboratory and dissected to investigate their reproductive status. Fungal gardens were constructed of whole mesquite leaves stacked together resembling a “house of cards”, and were covered with a thin coast of mycelium. The only other occurrence of this structure can be seen in the distantly related ant Acromyrmex sp., which uses grass as a fungal substrate. Amongst Trachymyrmex, this form of garden is unknown and is normally in the form of a tennis ball-size mass of disaggregated leaf substrate and fungal hyphae. Experiments to determine the substrate preference of foraging ants in regards to desert plants were also complete.