The gibberellins have come to be recognized as of major importance in the physiology of higher plants. The application of gibberellin has been shown to change the phenotype of many dwarf plants to that of the normal (1, 6). It has been found to replace the low temperature and long day requirements for flowering of a biennial plant (2), and to reverse the light inhibition of stem growth in dwarf and normal peas (3) and Perilla (4). Extracts containing gibberellin activity, as measured by the specific response of single-gene, dwarf mutants, have been made from the seed of several higher plants (9) ; providing final proof for the existence of gibberellin-like compounds in higher plants, and making virtually certain the assumption that the physiological responses indicated above are controlled in higher plants by native gibberellin-like compounds. One of the important physiological questions which arises in further investigations of the physiology of the gibberellins is the location of the region of production of the natural gibberellin factor in the plant. Specialization in plants is not so great as it is in the higher animals; nevertheless, the production of hormones has been found to be restricted to specific tissues in the higher plants. The leaves, roots, stem tip, or in seedlings, the cotyledons, have been shown to produce one or more hormones which act in the correlation and regulation of growth (cf 7). The present paper will present evidence indicating that the natural gibberellin factor, necessary for maximum stem elongation in normal pea seedlings, is produced in the stem tip.