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Published: February 25, 2015

One Fungus - Two Lichens

Robert Luecking, Research Associate, Gantz Family Collections Center
Lichen forming different lobes with green algae and cyanobacteria

Valentine's month comes to an end, and here we have another blog about lichen relationships. Lichens are a symbiotic relationship between a fungus and a green alga or a cyanobacterium. However, the reality is not that simple. Green algae and cyanobacteria have different physiological properties, allowing lichens to grow in different microhabitats. In addition, cyanobacteria are able to fix atmospheric nitrogen, which comes handy in nutrient-poor environments. While most lichens feature either a green alga or a cyanobacterium, some lichen fungi manage to associate with both at the same time. In such cases, the primary photobiont is a green alga and cyanobacteria are usually found in small pockets within the lichen, often invisible from the outside. Yet, occasionally the same fungus can form lichens that either contain green algae or cyanobacteria in separate lobes. This is shown here with the example of Pseudocyphellaria rufovirescens, a lichen common in New Zealand that usually forms lobes with green algae but often starts out associating with cyanobacteria. The two associations look very distinct and suggest that different lichen fungi are involved, but the only difference is the photobiont, which apparently then causes the lichen fungus to produce morphologically distinct lobes. The genetic base for this distinction is unknown and is subject of a collaborative project recently started by Field Museum lichenologists.

 


Robert Luecking

As former Collections Manager (2003-2015), I was responsible for the over 230,000 collections of fungi and lichens held at the Field Museum. As former Adjunct Curator (2001-2015) and now Research Associate, my research focuses on the taxonomy and systematics, phylogeny and evolution, ecology and biogeography, and applications of tropical lichens, mainly in the large families Gomphillaceae, Graphidaceae, Hygrophoraceae, Pilocarpaceae, Porinaceae, Pyrenulaceae, and Pilocarpaceae, which together contain nearly 3000 species. I am also familiar with lichens that grow on living leaves of vascular plants (foliicolous lichens). I am further interested in methodology, such as multivariate analysis in community ecology and phylogenetic methods. This including practical solutions to problems such as re-coding ambiguous regions in multiple fixed alignments of large datasets and their analysis under maximum likelihood, the assessment of homoplasy prior to tree building, and the phylogenetic placement of taxa for which no DNA data are available. I am a dedicated photographer focusing on nature and macrophotography.