New Mexico Office of Archaeological Studies

Ethnobotany Laboratory

Ethnobotany LabIf all we looked at in the Ethnobotany Lab were botanical specimens recognizable during excavation, we would have very little to do most of the time. Extraordinary preservation conditions (dry caves or rapidly smothered fires) would provide windfalls of abundant and varied plant materials, but for the most part, we'd be filing our fingernails and eating bonbons. Luckily, archaeologists know now that microscopic plant parts are recoverable from varied contexts in almost every archaeological site, using the inexpensive and environmentally friendly recovery technique of flotation.

The Ethnobotany Laboratory processes soil samples from all OAS excavations, as well as contracting with other agencies and individuals. The soil samples are poured into a bucket of water and agitated that causes the lighter botanical materials (called the light fraction) to float. These materials are decanted on to a piece of fine mesh material. This process is repeated until no further plant material is visible. The dried sample is then examined under a microscope to retrieve floral parts. The tiny seeds and charcoal fragments found in flotation samples provide information about resource selection for food and fuel, as well as the distribution of subsistence and manufacturing activities within sites. Changes in resource selection (between different geographic entities, between different regional site types, or over time) can reveal much about the choices available to prehistoric populations.

The Ethnobotany Lab personnel offer the following services:
• Modern vegetation surveys
• Flotation of soil samples
• Full-sort or scan analysis of flotation samples
• Macrobotanical sample analysis (including wood charcoal identification and morphometrics of maize cobs and kernels, beans, etc…)
• Reports of analysis results

For a current price list, please contact Executive Director John Taylor-Montoya ( or Director of Business Operations Thatcher Seltzer-Rogers ( or by phone at (505) 476-4404 or (505) 946-8413.

Examples of chapter reports can be viewed on this website among the OAS publications or provided by request.