Published online by Cambridge University Press: 28 March 2007
Two new species of Psoroma with unusual cephalodia are described: P. echinaceum with isidiate cephalodia, from southern South America and P. geminatum with fragile phyllidiate cephalodia, from New Zealand and Australia. These are additional to two previously described species producing dispersal units on their cephalodia, P. durietzii P.James & Henssen (with soredia) and P. aphthosum, Vain. (syn. nov. P. dimorphum Malme) (with isidia). This is a strategy development that ensures successful establishment of new thalli.