Relatively rare concentrations of ancient plant remains as caches and other forms of storage can provide important insights regarding many aspects of life not revealed by the typical archaeobotanical record. Before making archaeological interpretations it is important to determine if the source of an ancient plant concentration is the result of human storage and caching (cultural) or non-human animal nesting and caching (natural) activities, or a combination of both. This paper outlines key characteristics that can assist archaeobotanists in distinguishing between these two sources. Archaeological sites in the United States Southwest, with excellent examples of human caching and plant storage, are highlighted to show-case their interpretive potential for understanding ancient food security and storage capacity, resource diversity, and medicinal and ceremonial uses of plants. These rare seed caches and plant concentrations enhance our current understandings of plant use in the U.S. Southwest, and underscore how our interpretations can be limited by routinely encountered poorly preserved plant records.