Griffiths made this sensational claim about a figure on the frontispiece of Gerard's Herbal. He has cracked what he claims to be a secret Tudor code - but there is no code or secret to decipher.
The figure and the emblems associated in the engraving are linked with one man, Sir Francis Drake. It was Drake who brought corn (which the figure in the illustration is holding), tobacco and potatoes to England in 1586 when returning from the Roanoke colony. It was Drake who was associated with the Snake's Head Fritillary, which the figure is also holding, having being sent the flowers by Charles de L'Ecluse. John Gerard is depicted on the frontispiece holding a potato plant. This potato was given to him by none other than Francis Drake. Gerard's great innovation was to include descriptions of the exciting new plants from the Americas, whilst many of the older plants were based on an earlier work by Rembert Dodoens. We know that Gerard's description of the potato was based on what Drake told him. This was the first description of the potato in English literature.
Furthermore, the image in the engraving looks nothing like any existing images of Shakespeare but does look just like Francis Drake. This portrait of Drake, courtesy Philip Mould, is strikingly similar to the engraving.
Corn: Sir Francis Drake's West Indian Voyages, 1585-1586, Ashgate Publishing, 1991
Snake's Head Fritillary: Bulbs, A complete handbook, 1973