Dayflower (Commelina spp.) Seed Phytoliths at Archaeological Sites: A Microbotanical Indicator of Dayflower Utilization and a Potential Proxy Indicator of Agricultural Activities.

The genus Commelina has almost worldwide distribution. Species of Commelina have been utilized for subsistence and for medicinal purposes across the globe. Commelina and other members of the spiderwort family (Commelinaceae) are also well known as agricultural weeds, colonizers of disturbed soils and components of home gardens. Recent investigations have revealed that seeds from members of the Commelinaceae have siliceous coatings comprised of distinctive and unique phytolith bodies. Since 2008, I have documented the presence of Commelina seed phytoliths at 20 archaeological sites in North, Central, and South America. They have been recovered from a wide variety of contexts that include ground stone tools, ceramic residue, feature fill (middens, pits, hearths), and agricultural fields. Although the mostly low level of Commelina seed phytolith recovery at these sites suggests that the presence of this plant may simply be the result of anthropogenic disturbance, some findings suggest intentional exploitation of the seeds.