The American Historical Association's AHA Today blog has a nice post today about the wealth of information in the National Agricultural Library’s Special Collections online.

• The Special Collections of the National Agricultural Library, by Elisabeth Grant, AHA Today (February 01, 2010).

It includes Rare Books, Nursery and Seed Trade Catalogs, The Thomas Jefferson Correspondence Collection, the USDA Pomological [the science of fruit breeding and production] Watercolor Collection, and more.

See also the The National Agricultural Library Digital Repository (NALDR) which "provides access to primarily historical USDA publications either digitized by NAL or through NAL’s partnerships with other institutions."