Flora of New Zealand Series

Thallus hollow, white, straggling, unattached, on the ground or among decumbent vegetation or grass, subalpine to alpine. Photobiont green Trebouxia. Apothecia unknown.

Thamnolia contains two species, one of which is widely distributed in alpine localities in all parts of the world. This species, T. vermicularis, has two varieties ( var. subuliformis, and  var. vermicularis) which are morphologically indistinguishable, and which are separated by their chemistry. Both varieties occur in New Zealand [Sato Bryologist 68: 320-324 (1965)]. The genus is consistently sterile; however, its chemistry is close to that of the family Cladoniaceae. Thamnolia, Siphula and Endocaena are included in the family Siphulaceae. The widespread distribution of Thamnolia has provoked speculation on possible modes of its dispersal and associated problems of lichen biogeography [Culberson Brittonia 15: 140-144 (1963); Sato Nova Hedwigia 5: 149-155 (1963); Bull. Fac. Arts Sci. Ibaraki Univ. Nat. Sci. 16: 25-34 (1965); J. Jap. Bot. 43: 328-334 (1968); Sheard Bryologist 80: 100-118 (1977)].