Flora of New Zealand Series

Thallus foliose, lobate, dorsiventral, heteromerous, loosely attached. Lobes long, linear, narrow, subcanaliculate to involute, with or without marginal cilia. Lower surface channelled, brown to black, rhizinate or bare. Medulla white. Photobiont green, Trebouxia.

Cetrariastrum, included in the family Parmeliaceae, comprises c. 21 described species of mainly tropical America from Mexico and the West Indies to Chile, Southern Brazil and Argentina [Hale Mycotaxon 3: 345-353 (1976); Sipman Proc. K. ned. Akad. Wet. ser. C, 83 (4): 333-354 (1980); Culberson and Culberson Bryologist 84: 273-314 (1981)]. Of the known species four occur also in Asia and C. sorocheilum is in the Canary Islands. One species occurs in New Zealand.