Concerning reliability and unreliability of dried pollen from commercial sources

Abstract

1. 1. By microscopic examinations of 260 different lots of dry pollen purchased from commercial sources, 68.1 per cent were found authentic and uncontaminated, 20 per cent were contaminated but slightly, and 10.4 per cent of the contamination was “natural” in character, 6.5 per cent was incorrectly labeled, and 5.4 per cent were seriously contaminated. 2. 2. Examination for certification of dried pollen to be used for extraction should be universally required.