Sanderson's Prize essay manuscript, ‘The Origin and Development of the Embryo in Phanerogamous Plants’, submitted in July 1849 as part of his Botany course for his Medical degree at the University of Edinburgh. Sanderson has illustrated the manuscript with pencil illustrations drawn from the microscope.
Impressed by the content, Hutton Balfour deemed it worthy of a prize, with part of the content read at a meeting of the Botanical Society of Edinburgh in February 1850.
Manuscript titled 'Localities for New or Rare Mosses in Scotland'.
The names Alexander McKinlay, James Stirton and John Shaw are mentioned as collectors in the manuscript, alongside three dates, 1861, 1864 and 1868. Although not definite, the handwriting in the documents compares very favourably to that of James Hardy (1815-1898), Secretary of the Berwickshire Naturalists Club and compiling a work on Mosses of Berwickshire at the end of the 1860s.