Seeing clearly - Plant anatomy through Katherine Esau's microscopy lens.

Describing, naming and understanding the tissues and cell types composing biological organisms underpin myriad research endeavours in the biosciences. This is obvious when the organismal structure is a direct subject of the investigation such as in analyses of structure-function relationships. However, it also applies when structure represents the context. Gene expression networks and physiological processes cannot be divorced from the spatial and structural framework of the organs in which they operate. Atlases of anatomy and a precise vocabulary are therefore key tools on which modern scientific endeavours in the life sciences are based. One of the seminal authors whose books are familiar to nearly everyone in the plant biology community is Katherine Esau (1898-1997), a phenomenal plant anatomist and microscopist whose textbooks are still used daily around the world - 70 years after their first publication. Several technical innovations in microscopy have emerged since Esau's time and plant biological studies by authors who were trained using her books are shown side-by-side with Esau's drawings.