Abstract
Here we use the term ‘algae’ to refer to the broad, polyphyletic assemblage of photosynthetic life forms exclusive of the embryophytes, as do contemporary phycology textbooks. Almost all algae found in lichen associations are either green (chlorophytes) or blue‐green (cyanophytes/cyanobacteria); two lichens with heterokontophyte algal symbionts are also known ( Tschermak‐Woess, 1988 ). The widely used term ‘phycobiont’ is applied to all these algal symbionts.