Fascinating. The catalog "Steichen: the Master Prints" from the Museum of Modern Art features as a frontispiece a similar autochrome (to the upper reproduction in the article) titled "Young Girl Standing beside a Vase of Daffodils, c. 1908" obviously taken at the same time (same woman, same dress, same daffodils, same vase, same background) but a different pose. It is identified as belonging to the Philadelphia Museum of Art.