Definition of old man's beard in US English:

old man's beard

noun

  • 1A wild clematis that has gray fluffy hairs around the seeds.

    Genus Clematis, family Ranunculaceae: several species, in particular traveler's joy and virgin's bower

    • ‘Other plants in the ecozone include salal, Oregon grape, arbutus, sword fern, skunk cabbage, salmonberry, devil's club, western bleeding heart, red huckleberry, old man's beard, red elderberry, calypso orchid, and Viola langsdorfii’
    • ‘The importance of removing the true nasties - old man's beard, ginger, wandering willy - from the forest floor is easy to understand, at least to anyone who has witnessed the devastation that these plants can do.’
    • ‘Ragwort and old man's beard also have to be controlled.’
  • 2A large lichen that forms shaggy grayish growths on the branches of trees.

    Usnea barbata and related species, order Parmeliales

    • ‘The forest canopy is a deep blue-green, tinged with pale-green old man's beard, uniformly towering above the mosses and berry bushes.’