I can only imagine this refers to a patchy or spotted colour combination, as ‘pard’ means leopard or panther, or another animal resembling either.

‘Perhaps this permanent pard-like stubble …’

Source: Patrick Leigh Fermor, Mani: Travels in the Southern Peloponnese, introduction by Michael Gorra, New York: New York Review of Books, 2006 (1958), p. 317