There is growing evidence for human use of geophytes long before the advent of agriculture. Rich in carbohydrates, geophytes were important in many coastal areas where protein-rich marine foods are abundant. On California's Channel Islands, scholars have long questioned how maritime peoples sustained themselves for millennia with limited plant resources. Recent research demonstrates that geophytes were heavily used on the islands for 10,000 years, and here we describe geophyte and other archaeobotanical remains from an approximately 11,500-year-old site on Santa Rosa Island. Currently the earliest evidence for geophyte consumption in North America, our data extend geophyte use on the Channel Islands by roughly 1,500 years and document a diverse and balanced economy for early Paleocoastal peoples. Experimental return rates for a key island geophyte support archaeological evidence that the corms of blue dicks (Dipterostemon capitatus) were a high-ranked staple resource throughout the Holocene.
