On extraction of timothy pollen with aqueous buffer high molecular weight material (MW > 3,500) containing the sugars arabinose, fucose, xylose, mannose, galactose and glucose was rapidly released. When the allergen extract was subjected to crossed immunoaffinoelectrophoresis with lectins incorporated in the first- or second-dimension gel, some allergens were clearly retarded. A basic glycoprotein allergen, probably the one known as antigen 30, was bound to concanavalin A (Con A) and also to a lectin from Pisum sativum. This allergen was purified by a combination of Con A-Sepharose and CM-Sephadex chromatography, giving a product that contained the following sugars: arabinose (1.4%), fucose (traces), xylose (1.3%), mannose (2.0%), galactose (7.6%) and glucose (10.5%). The purified allergen appeared essentially homogeneous on isoelectric focusing and on gel permeation chromatography. The allergenic activity and acid phosphatase activity, which have been correlated by previous workers, were demonstrated to be entirely separable.