We are so often attracted to flowers by their stunning and vibrant colours — a lemon yellow daffodil or a deep red rose. But back in the early 20th century a radiologist, Dr Dain Tasker, was interested in the anatomy of flowers using his professional skills and X-ray film to highlight the soft layering of petals and leaves. This produced ghostly, monochrome images looking more like pen & ink drawings than photographs.

Fuchsia, 1938, vintage gelatin silver print, 24x18cm
There is more information and more images on Colossal and Hyperallergic.