Definition of "gnarled"

Three chairs of the steamer type, all maimed, comprised the furniture of this roof-garden, with […] on one of the copings a row of four red clay flower-pots filled with sun-baked dust from which gnarled and rusty stalks thrust themselves up like withered elfin limbs.

1914, Louis Joseph Vance, chapter I, in Nobody, New York, N.Y.: George H[enry] Doran Company, published 1915