Niebla undulata is distinguished by a bluish green thallus to 6 cm high and 6 cm broad, divided into curly ribbon-like branches from a short tubular base, and by the presence of the lichen metabolite divaricatic acid, with triterpenes.

The primary branches, which are less than 20 in number, are loosely connected at base to a yellowish pigmented holdfast, blackened slightly above base, curved upwards or widely spread apart, sometimes horizontally to the extent that they creep along the rock, and they are undulate both broadly and shortly along margins.

[1] Niebla undulata was recognized in regard to pursuing a lichen flora of Baja California beginning May 1986.

The species (N. undulata) was found to occur frequently on pebble size lava of mesas and leeward slopes.

[1] These differences are geographical, and also appearing related to the associated species in the Niebla community or population;[1] this might be indicative of occasional hybridization.