Possible Clues:

• 9's ending makes you bristle
• Head is buried in pale bristly growth
• Bristle-like appendage on grass
• Beard growing out of an ear
• Botanist's beard
• Bristle in flowering part of some grasses
• Female shaved off flatter beard
• Wheat part
• Three-quarters of the grass is enough to make one bristle
• After half a century, the grass would have whiskers like this