Domain:     Eukaryota
Kingdom:   Viridiplantae
Phylum:     Chlorophyta
Class:        Ulvophyceae
Order:       Trentepohliales
Family:      Trentepohliaceae
Genus:      Trentepohlia
Species:   Trentepohlia spp 

Trentepohlia is a genus of filamentous green chlorophyte algae, specifically of the family Trentepohliaceae, living free on terrestrial supports such as tree trunks and wet rocks or symbiotically in lichens.
The filaments of Trentepohlia have a strong orange colour. The green chlorophyll pigment is masked by the presence of large amounts of β-carotene, the same photosynthetic pigment that causes the orange colouration of most carrots. This colour was found to be the source of an incident of red rain in Kerala, India.
Trentepohlia species form associations with fungal hyphae and are widespread phycobionts in lichens.

The appearance of Trentepohlia so closely resembles a lichen that it warrants its place in the lichen identification keys.

Photographed on a papa wall entrance at the Moki tunnel (Taranaki).
Algae Trentepohlia spp .JPG

Algae Trentepohlia spp -001.JPG 

Algae Trentepohlia spp 7.JPG

Algae Trentepohlia spp -002.JPG 

Thanks to Wikipedia for text and information: