cinereous
/sɪˈnɪərɪəs
/adjective
(Especially of hair or feathers) ash-grey.The stems are covered with several barks or rinds, the latter being of a cinereous dirt color and very thin.
Origin
Late Middle English: from Latin cinereus 'similar to ashes' (from cinis, ciner- 'ashes') + -ous.