We prefer university extension, public agencies, primary historical materials, and direct documentation. These sources support general educational context; they do not establish TEXAS YAPA’s supplier claims, product specifications, caffeine quantity, or commercial compliance.
Texas A&M Forest Service
Trees of Texas: Yaupon (Ilex vomitoria) ↗
Texas range, evergreen leaves, plant description, berries, and caffeine-containing leaves.
https://texastreeid.tfs.tamu.edu/content/TreeDetails/?id=49Texas A&M AgriLife Extension
Plants of Texas Rangelands: Yaupon ↗
Botanical description, habitat, distribution, wildlife relationships, and plant characteristics.
https://rangeplants.tamu.edu/plant/yaupon/Florida Department of State · Division of Historical Resources
The Yaupon ↗
Historical overview of yaupon beverage traditions among Indigenous peoples in the Southeast and the colonial term “black drink.”
https://dos.fl.gov/historical/museums/historical-museums/united-connections/foodways/foodways-of-native-floridians/the-yaupon/University of Florida IFAS Extension
Yaupon Holly (Ilex vomitoria) ↗
Plant identification, growth habit, flowers, fruit, and ecological relationships.
https://gardeningsolutions.ifas.ufl.edu/mastergardener/resources/plantid/ornamentals/yaupon-holly/USDA Natural Resources Conservation Service
Yaupon Plant Guide ↗
Additional botanical and ethnobotanical background. This is an older guide and should be read with its publication date in mind.
https://plants.usda.gov/DocumentLibrary/plantguide/pdf/cs_ilvo.pdfHistorical accounts can reflect the perspective and terminology of the writers who recorded them. We will continue to seek Indigenous-authored and nation-specific sources as the educational section develops, and will not claim to speak for Indigenous communities.